# JAO Data Treatment & Feature Extraction Plan
## Complete Guide for FBMC Flow Forecasting MVP

**Last Updated:** October 29, 2025  
**Project:** FBMC Zero-Shot Forecasting with Chronos 2  
**Timeline:** 5-Day MVP  
**Version:** 5.0 - OUTAGE DURATION FEATURES (Added temporal outage metrics for enhanced forecasting)  

---

## Table of Contents

1. [Data Acquisition Strategy](#1-data-acquisition-strategy)
2. [JAO Data Series Catalog](#2-jao-data-series-catalog)
3. [Data Cleaning Procedures](#3-data-cleaning-procedures)
4. [CNEC Treatment](#4-cnec-treatment)
5. [PTDF Treatment](#5-ptdf-treatment)
6. [RAM Treatment](#6-ram-treatment)
7. [Shadow Prices Treatment](#7-shadow-prices-treatment)
8. [Feature Engineering Pipeline](#8-feature-engineering-pipeline)
9. [Quality Assurance](#9-quality-assurance)

---

## 1. Data Acquisition Strategy

### 1.1 Timeline and Scope

**Historical Data Period:** October 2023 - September 2025 (24 months)
- Purpose: Feature baselines and historical context
- Total: ~17,520 hourly records per series

**Collection Priority:**
1. **Day 1 Morning (2 hours):** Max BEX files (TARGET VARIABLE - highest priority!)
2. **Day 1 Morning (2 hours):** CNEC files (critical for constraint identification)
3. **Day 1 Morning (2 hours):** PTDF matrices (network sensitivity)
4. **Day 1 Afternoon (1.5 hours):** LTN values (future covariates)
5. **Day 1 Afternoon (1.5 hours):** Min/Max Net Positions (domain boundaries)
6. **Day 1 Afternoon (1.5 hours):** ATC Non-Core borders (loop flow drivers)
7. **Day 1 Afternoon (1.5 hours):** RAM values (capacity margins)
8. **Day 1 Afternoon (1.5 hours):** Shadow prices (economic signals)

### 1.2 jao-py Python Library Usage

**Installation & Setup:**
```bash
# Install jao-py using uv package manager
.venv/Scripts/uv.exe pip install jao-py>=0.6.2

# Verify installation
.venv/Scripts/python.exe -c "from jao import JaoPublicationToolPandasClient; print('jao-py installed successfully')"
```

**Python Data Collection:**
```python
import pandas as pd
from jao import JaoPublicationToolPandasClient
import time

# Initialize client (no API key required for public data)
client = JaoPublicationToolPandasClient()

# Define date range (24 months: Oct 2023 - Sept 2025)
# IMPORTANT: jao-py requires pandas Timestamp with timezone (UTC)
start_date = pd.Timestamp('2023-10-01', tz='UTC')
end_date = pd.Timestamp('2025-09-30', tz='UTC')

# Collect MaxBEX data (TARGET VARIABLE) - day by day with rate limiting
maxbex_data = []
current_date = start_date
while current_date <= end_date:
    df = client.query_maxbex(current_date)
    maxbex_data.append(df)
    current_date += pd.Timedelta(days=1)
    time.sleep(5)  # Rate limiting: 5 seconds between requests

# Combine and save
maxbex_df = pd.concat(maxbex_data)
maxbex_df.to_parquet('data/raw/jao/maxbex_2023_2025.parquet')

# Collect Active Constraints (CNECs + PTDFs in ONE call!)
cnec_data = []
current_date = start_date
while current_date <= end_date:
    df = client.query_active_constraints(current_date)
    cnec_data.append(df)
    current_date += pd.Timedelta(days=1)
    time.sleep(5)  # Rate limiting: 5 seconds between requests

# Combine and save
cnec_df = pd.concat(cnec_data)
cnec_df.to_parquet('data/raw/jao/cnecs_ptdfs_2023_2025.parquet')
```

**Key Methods Available:**
- `query_maxbex(day)` - Maximum Bilateral Exchange capacity (TARGET)
- `query_active_constraints(day)` - CNECs with shadow prices, RAM, and PTDFs
- `query_lta(d_from, d_to)` - Long Term Allocations (perfect future covariate)
- `query_minmax_np(day)` - Min/Max Net Positions (domain boundaries)
- `query_net_position(day)` - Actual net positions
- `query_monitoring(day)` - Monitoring data (additional RAM/shadow prices)
```

**Expected Output Files:**
```
data/raw/jao/
├── cnecs_2024_2025.parquet         (~500 MB)
├── ptdfs_2024_2025.parquet         (~800 MB)
├── rams_2024_2025.parquet          (~400 MB)
├── shadow_prices_2024_2025.parquet (~300 MB)
├── presolved_2024_2025.parquet     (~200 MB)
├── d2cf_2024_2025.parquet          (~600 MB - OPTIONAL)
└── metadata/
    ├── cnec_definitions.parquet
    ├── zone_ptdf_mapping.parquet
    └── download_log.json
```

---

## 2. JAO Data Series Catalog

### 2.1 Max BEX Data Series (TARGET VARIABLE)

**File:** `Core_DA_Results_[date].xml` or `Core_Max_Exchanges_[date].xml` 

**CRITICAL:** This is the **TARGET VARIABLE** we are forecasting - without Max BEX, the model cannot be trained or evaluated!

| Field Name | Data Type | Description | Use in Features | Missing Value Strategy |
|------------|-----------|-------------|-----------------|----------------------|
| `border_id` | String | Border identifier (e.g., "DE-FR", "DE-NL") | Border tracking | **REQUIRED** |
| `timestamp` | Datetime | Delivery hour | Time index | **REQUIRED** |
| `max_bex` | Float (MW) | Maximum Bilateral Exchange Capacity | **TARGET VARIABLE** | **CRITICAL - must have** |
| `direction` | String | Direction of capacity (e.g., "DE→FR") | Directional features | Parse from border |

**Description:**
Max BEX represents the **actual available cross-border capacity** after FBMC optimization. It is the OUTPUT of the FBMC calculation process and represents how much capacity is actually available for bilateral exchanges after accounting for:
- All CNEC constraints (RAM limits)
- PTDF sensitivities
- LTN allocations (capacity already committed)
- Remedial actions
- All network constraints

**IMPORTANT: Commercial vs Physical Capacity**
- MaxBEX = **commercial hub-to-hub trading capacity**, NOT physical interconnector ratings
- FBMC Core has 12 bidding zones: AT, BE, CZ, DE-LU, FR, HR, HU, NL, PL, RO, SI, SK
- **All 132 zone-pair combinations exist** (12 × 11 bidirectional pairs)
- This includes "virtual borders" - zone pairs without direct physical interconnectors
- Example: FR→HU capacity exists despite no physical FR-HU interconnector
  - Power flows through AC grid network via DE, AT, CZ
  - PTDFs quantify how this exchange affects every CNEC in the network
  - MaxBEX = optimization result considering ALL network constraints

**Borders to Collect (ALL 132 zone pairs):**
- JAO provides MaxBEX for all 12 × 11 = 132 bidirectional zone-pair combinations
- Includes both physical borders (e.g., DE→FR, AT→CZ) and virtual borders (e.g., FR→HU, BE→PL)
- Each direction (A→B vs B→A) has independent capacity values
- Full list: All permutations of (AT, BE, CZ, DE, FR, HR, HU, NL, PL, RO, SI, SK)
- Example physical borders: DE→FR, DE→NL, AT→CZ, BE→NL, FR→BE
- Example virtual borders: FR→HU, AT→HR, BE→RO, NL→SK, CZ→HR

**Collection Priority:** DAY 1 MORNING (FIRST PRIORITY)
This is the ground truth for training and validation - collect before any other data series!

**Storage Schema:**
```python
max_bex_schema = {
    'timestamp': pl.Datetime,
    'border_id': pl.Utf8,
    'max_bex': pl.Float32,        # TARGET VARIABLE
    'direction': pl.Utf8
}
```

**Expected File Size:** ~1.2-1.5 GB for 24 months × 132 zone pairs × 17,520 hours (actual: ~200 MB compressed as Parquet)

---

### 2.2 LTN Data Series (Long Term Nominations)

**File:** `Core_LTN_[date].xml` or available through `Core_ltn.R` JAOPuTo function

**CRITICAL:** LTN values are **PERFECT FUTURE COVARIATES** because they result from yearly/monthly capacity auctions and are known with certainty for the forecast horizon!

| Field Name | Data Type | Description | Use in Features | Missing Value Strategy |
|------------|-----------|-------------|-----------------|----------------------|
| `border_id` | String | Border identifier (e.g., "DE-FR", "SI-HR") | Border tracking | **REQUIRED** |
| `timestamp` | Datetime | Delivery hour | Time index | **REQUIRED** |
| `ltn_allocated` | Float (MW) | Capacity already allocated in long-term auctions | **INPUT FEATURE & FUTURE COVARIATE** | 0.0 (no LT allocation) |
| `direction` | String | Direction of nomination | Directional features | Parse from border |
| `auction_type` | String | "yearly" or "monthly" | Allocation source tracking | Required field |

**Description:**
LTN represents capacity already committed through long-term (yearly and monthly) auctions conducted by JAO. This capacity is **guaranteed and known in advance**, making it an exceptionally valuable feature:

**Historical Context (What Happened):**
- LTN values show how much capacity was already allocated
- Higher LTN → lower available day-ahead capacity (Max BEX)
- Direct relationship: `Max BEX ≈ Theoretical Max - LTN - Other Constraints`

**Future Covariates (What We Know Will Happen):**
- **Yearly auctions:** Results are known for the **entire year ahead**
- **Monthly auctions:** Results are known for the **month ahead**
- When forecasting D+1 to D+14, LTN values are **100% certain** (already allocated)
- This is **GOLD STANDARD** for future covariates - no forecasting needed!

**Borders with LTN:**
Most Core borders have LTN=0 (Financial Transmission Rights), but important exceptions:
- **SI-HR** (Slovenia-Croatia): Physical Transmission Rights (PTRs) still in use
- Some external Core borders may have PTRs
- Even when LTN=0, including the series confirms this to the model

**Impact on Max BEX:**
Example: If DE-FR has 500 MW LTN allocated:
- Theoretical capacity: 3000 MW
- LTN reduction: -500 MW
- After network constraints: -400 MW
- **Result: Max BEX ≈ 2100 MW**

**Collection Priority:** DAY 1 AFTERNOON (HIGH PRIORITY - future covariates)

**Storage Schema:**
```python
ltn_schema = {
    'timestamp': pl.Datetime,
    'border_id': pl.Utf8,
    'ltn_allocated': pl.Float32,      # Amount already committed
    'direction': pl.Utf8,
    'auction_type': pl.Utf8           # yearly/monthly
}
```

**Expected File Size:** ~100-160 MB for 24 months × 20 borders × 17,520 hours

**JAOPuTo Download Command:**
```bash
# Download LTN data for 24 months
java -jar JAOPuTo.jar \
  --start-date 2023-10-01 \
  --end-date 2025-09-30 \
  --data-type LTN \
  --region CORE \
  --output-format parquet \
  --output-dir ./data/raw/jao/ltn/
```

**Future Covariate Usage:**
```python
# LTN is known in advance from auction results
# For forecast period D+1 to D+14, we have PERFECT information
def prepare_ltn_future_covariates(ltn_df, forecast_start_date, prediction_horizon_hours=336):
    """
    Extract LTN values for future forecast horizon
    These are KNOWN with certainty (auction results)
    """
    forecast_end_date = forecast_start_date + pd.Timedelta(hours=prediction_horizon_hours)
    
    future_ltn = ltn_df.filter(
        (pl.col('timestamp') >= forecast_start_date) &
        (pl.col('timestamp') < forecast_end_date)
    )
    
    return future_ltn  # No forecasting needed - these are actual commitments!
```

---

### 2.3 Min/Max Net Position Data Series

**File:** `Core_MaxNetPositions_[date].xml` or available through `Core_maxnetpositions.R` JAOPuTo function

**CRITICAL:** Min/Max Net Positions define the **feasible domain** for each bidding zone - the boundaries within which net positions can move without violating network constraints.

| Field Name | Data Type | Description | Use in Features | Missing Value Strategy |
|------------|-----------|-------------|-----------------|----------------------|
| `zone` | String | Bidding zone (e.g., "DE_LU", "FR", "BE") | Zone tracking | **REQUIRED** |
| `timestamp` | Datetime | Delivery hour | Time index | **REQUIRED** |
| `net_pos_min` | Float (MW) | Minimum feasible net position | **DOMAIN BOUNDARY** | **CRITICAL - must have** |
| `net_pos_max` | Float (MW) | Maximum feasible net position | **DOMAIN BOUNDARY** | **CRITICAL - must have** |
| `actual_net_pos` | Float (MW) | Actual net position after market clearing | Reference value | 0.0 if missing |

**Description:**
Min/Max Net Positions represent the **feasible space** in which each bidding zone can operate without violating any CNEC constraints. These values are extracted from the union of:
- Final flow-based domain
- Final bilateral exchange restrictions (LTA inclusion)
- All CNEC constraints simultaneously satisfied

**Why This Matters for Forecasting:**
1. **Tight ranges indicate constrained systems:**
   - If `net_pos_max - net_pos_min` is small → limited flexibility → likely lower Max BEX
   - If range is large → system has degrees of freedom → potentially higher Max BEX

2. **Zone-specific stress indicators:**
   - A zone with narrow net position range is "boxed in"
   - This propagates to adjacent borders (reduces their capacity)

3. **Derived features:**
   ```python
   # Range = degrees of freedom
   net_pos_range = net_pos_max - net_pos_min
   
   # Margin = how close to limits (utilization)
   net_pos_margin = (actual_net_pos - net_pos_min) / (net_pos_max - net_pos_min)
   
   # Stress index = inverse of range (tighter = more stressed)
   zone_stress = 1.0 / (net_pos_range + 1.0)  # +1 to avoid division by zero
   ```

**Example Interpretation:**
For Germany (DE_LU) at a specific hour:
- `net_pos_min` = -8000 MW (maximum import)
- `net_pos_max` = +12000 MW (maximum export)
- `actual_net_pos` = +6000 MW (actual export after market clearing)
- **Range** = 20,000 MW (large flexibility)
- **Margin** = (6000 - (-8000)) / 20000 = 0.70 (70% utilization toward export limit)

If another hour shows:
- `net_pos_min` = -2000 MW
- `net_pos_max` = +3000 MW
- **Range** = 5,000 MW (VERY constrained - system is tight!)
- This hour will likely have lower Max BEX on German borders

**Zones to Collect (12 Core zones):**
- DE_LU (Germany-Luxembourg)
- FR (France)
- BE (Belgium)
- NL (Netherlands)
- AT (Austria)
- CZ (Czech Republic)
- PL (Poland)
- SK (Slovakia)
- HU (Hungary)
- SI (Slovenia)
- HR (Croatia)
- RO (Romania)

**Collection Priority:** DAY 1 AFTERNOON (HIGH PRIORITY)

**Storage Schema:**
```python
netpos_schema = {
    'timestamp': pl.Datetime,
    'zone': pl.Utf8,
    'net_pos_min': pl.Float32,        # Minimum feasible (import limit)
    'net_pos_max': pl.Float32,        # Maximum feasible (export limit)
    'actual_net_pos': pl.Float32      # Actual market clearing value
}
```

**Expected File Size:** ~160-200 MB for 24 months × 12 zones × 17,520 hours

**JAOPuTo Download Command:**
```bash
# Download Min/Max Net Positions for 24 months
java -jar JAOPuTo.jar \
  --start-date 2023-10-01 \
  --end-date 2025-09-30 \
  --data-type MAX_NET_POSITIONS \
  --region CORE \
  --output-format parquet \
  --output-dir ./data/raw/jao/netpos/
```

**Feature Engineering:**
```python
def engineer_netpos_features(df: pl.DataFrame) -> pl.DataFrame:
    """
    Create net position features from Min/Max data
    """
    df = df.with_columns([
        # 1. Range (degrees of freedom)
        (pl.col('net_pos_max') - pl.col('net_pos_min'))
        .alias('net_pos_range'),
        
        # 2. Utilization margin (0 = at min, 1 = at max)
        ((pl.col('actual_net_pos') - pl.col('net_pos_min')) / 
         (pl.col('net_pos_max') - pl.col('net_pos_min')))
        .alias('net_pos_margin'),
        
        # 3. Stress index (inverse of range, normalized)
        (1.0 / (pl.col('net_pos_max') - pl.col('net_pos_min') + 100.0))
        .alias('zone_stress_index'),
        
        # 4. Distance to limits (minimum of distances to both boundaries)
        pl.min_horizontal([
            pl.col('actual_net_pos') - pl.col('net_pos_min'),
            pl.col('net_pos_max') - pl.col('actual_net_pos')
        ]).alias('distance_to_nearest_limit'),
        
        # 5. Asymmetry (is the feasible space symmetric around zero?)
        ((pl.col('net_pos_max') + pl.col('net_pos_min')) / 2.0)
        .alias('domain_asymmetry')
    ])
    
    return df
```

**System-Level Aggregations:**
```python
def aggregate_netpos_system_wide(df: pl.DataFrame) -> pl.DataFrame:
    """
    Create system-wide net position stress indicators
    """
    system_features = df.groupby('timestamp').agg([
        # Average range across all zones
        pl.col('net_pos_range').mean().alias('avg_zone_flexibility'),
        
        # Minimum range (most constrained zone)
        pl.col('net_pos_range').min().alias('min_zone_flexibility'),
        
        # Count of highly constrained zones (range < 5000 MW)
        (pl.col('net_pos_range') < 5000).sum().alias('n_constrained_zones'),
        
        # System-wide stress (average of zone stress indices)
        pl.col('zone_stress_index').mean().alias('system_stress_avg'),
        
        # Maximum zone stress (tightest zone)
        pl.col('zone_stress_index').max().alias('system_stress_max')
    ])
    
    return system_features
```

---

### 2.4 CNEC Data Series

**File:** `Core_DA_CC_CNEC_[date].xml` (daily publication at 10:30 CET)

| Field Name | Data Type | Description | Use in Features | Missing Value Strategy |
|------------|-----------|-------------|-----------------|----------------------|
| `cnec_id` | String | Unique identifier (e.g., "DE_CZ_TIE_001") | CNEC tracking | N/A - Required field |
| `cnec_name` | String | Human-readable name (e.g., "Line Röhrsdorf-Hradec N-1 ABC") | Documentation | Forward-fill |
| `contingency` | String | N-1 element causing constraint | CNEC classification | "basecase" if missing |
| `tso` | String | Responsible TSO (e.g., "50Hertz", "ÄŒEPS") | Geographic features | Parse from `cnec_id` |
| `monitored_element` | String | Physical line/transformer being monitored | CNEC grouping | Required field |
| `fmax` | Float (MW) | Maximum flow limit under contingency | Normalization baseline | **CRITICAL - must have** |
| `ram_before` | Float (MW) | Initial remaining available margin | Historical patterns | 0.0 (conservative) |
| `ram_after` | Float (MW) | Final RAM after remedial actions | **Primary feature** | Forward-fill from `ram_before` |
| `flow_fb` | Float (MW) | Final flow after market coupling | Flow patterns | 0.0 if unconstrained |
| `presolved` | Boolean | Was CNEC binding/active? | **Key target feature** | False (not binding) |
| `shadow_price` | Float (€/MW) | Lagrange multiplier for constraint | Economic signal | 0.0 if not binding |
| `direction` | String | "import" or "export" from perspective | Directionality | Parse from flow sign |
| `voltage_level` | Integer (kV) | Voltage level (e.g., 220, 380) | CNEC classification | 380 (most common) |
| `timestamp` | Datetime | Delivery hour (CET/CEST) | Time index | **REQUIRED** |
| `business_day` | Date | Market day (D for delivery D+1) | File organization | Derive from timestamp |

**Storage Schema:**
```python
cnec_schema = {
    'timestamp': pl.Datetime,
    'business_day': pl.Date,
    'cnec_id': pl.Utf8,
    'cnec_name': pl.Utf8,
    'tso': pl.Utf8,
    'fmax': pl.Float32,
    'ram_after': pl.Float32,      # Primary field
    'ram_before': pl.Float32,
    'flow_fb': pl.Float32,
    'presolved': pl.Boolean,
    'shadow_price': pl.Float32,
    'contingency': pl.Utf8,
    'voltage_level': pl.Int16
}
```

**Collection Decision:**
- ✅ **COLLECT:** All fields above
- ❌ **SKIP:** Internal TSO-specific IDs, validation flags, intermediate calculation steps

### 2.5 PTDF Data Series

**File:** `Core_DA_CC_PTDF_[date].xml` (published D-2 and updated D-1)

| Field Name | Data Type | Description | Use in Features | Missing Value Strategy |
|------------|-----------|-------------|-----------------|----------------------|
| `cnec_id` | String | Links to CNEC | Join key | **REQUIRED** |
| `zone` | String | Bidding zone (e.g., "DE_LU", "FR") | Sensitivity mapping | **REQUIRED** |
| `ptdf_value` | Float | Sensitivity coefficient (-1.0 to +1.0) | **Core feature** | 0.0 (no impact) |
| `timestamp` | Datetime | Delivery hour | Time index | **REQUIRED** |
| `version` | String | "D-2" or "D-1" | Data freshness | Use latest available |
| `is_hvdc` | Boolean | Is this a HVDC link sensitivity? | Separate treatment | False |

**PTDF Matrix Structure:**
```
              DE_LU    FR     NL     BE     AT     CZ     PL     ... (12 zones)
CNEC_001      0.42   -0.18   0.15   0.08   0.05   0.12  -0.02   ...
CNEC_002     -0.35    0.67  -0.12   0.25   0.03  -0.08   0.15   ...
CNEC_003      0.28   -0.22   0.45  -0.15   0.18   0.08  -0.05   ...
...
CNEC_200      ...     ...    ...    ...    ...    ...    ...    ...
```

**Collection Decision:**
- ✅ **COLLECT:** `ptdf_value` for all zones × all CNECs × all hours
- ✅ **COLLECT:** Only "D-1" version (most recent available for historical data)
- ❌ **SKIP:** D-2 version, intermediate updates, HVDC-specific matrices

**Dimensionality:**
- Raw: ~200 CNECs × 12 zones × 17,520 hours = ~42 million values
- **Hybrid Storage:** Top 50 CNECs with individual PTDFs, Tier-2 with border aggregates

### 2.6 RAM Data Series

**File:** `Core_DA_CC_CNEC_[date].xml` (within CNEC records)

| Field Name | Data Type | Description | Use in Features | Missing Value Strategy |
|------------|-----------|-------------|-----------------|----------------------|
| `cnec_id` | String | CNEC identifier | Join key | **REQUIRED** |
| `timestamp` | Datetime | Delivery hour | Time index | **REQUIRED** |
| `minram` | Float (MW) | Minimum RAM (70% rule) | Compliance checking | 0.7 × fmax |
| `initial_ram` | Float (MW) | RAM before coordination | Historical baseline | Forward-fill |
| `final_ram` | Float (MW) | RAM after validation/remedial actions | **Primary feature** | **CRITICAL** |
| `ram_net_position` | Float (MW) | Net position at which RAM calculated | Market condition | 0.0 |
| `validation_adjustment` | Float (MW) | TSO adjustments during validation | Adjustment patterns | 0.0 |
| `remedial_actions_applied` | Boolean | Were remedial actions used? | Constraint stress | False |

**Collection Decision:**
- ✅ **COLLECT:** `final_ram`, `minram`, `initial_ram`
- ✅ **COLLECT:** `remedial_actions_applied` (binary indicator)
- ❌ **SKIP:** Detailed remedial action descriptions (too granular)

### 2.7 Shadow Price Data Series

**File:** `Core_DA_Results_[date].xml` (post-market publication)

| Field Name | Data Type | Description | Use in Features | Missing Value Strategy |
|------------|-----------|-------------|-----------------|----------------------|
| `cnec_id` | String | CNEC identifier | Join key | **REQUIRED** |
| `timestamp` | Datetime | Delivery hour | Time index | **REQUIRED** |
| `shadow_price` | Float (€/MW) | Lagrange multiplier | Economic signal | 0.0 |
| `shadow_price_before_minram` | Float (€/MW) | Before 70% rule applied | Pre-constraint value | 0.0 |
| `binding_duration` | Integer (minutes) | How long CNEC was binding | Persistence | 0 |
| `peak_shadow_price_4h` | Float (€/MW) | Max in 4-hour window | Volatility signal | shadow_price |

**Collection Decision:**
- ✅ **COLLECT:** `shadow_price` (primary)
- ✅ **COLLECT:** `binding_duration` (for persistence features)
- ❌ **SKIP:** `shadow_price_before_minram` (less relevant for forecasting)

---

### 2.8 D2CF (Day-2 Congestion Forecast) - OPTIONAL

**Decision: SKIP for MVP**

**Rationale:**
1. **Temporal misalignment:** D2CF provides TSO forecasts for D+2, but we're forecasting D+1 to D+14
2. **Forecast contamination:** These are forecasts, not ground truth - introduces noise
3. **Better alternatives:** ENTSO-E actual generation/load provides cleaner signals
4. **Scope reduction:** Keeps MVP focused on high-signal features

**If collected later:**
- `load_forecast_d2cf`: TSO load forecast
- `generation_forecast_d2cf`: TSO generation forecast  
- `net_position_forecast_d2cf`: Expected net position

---

### 2.9 ATC for Non-Core Borders Data Series

**File:** `Core_ATC_External_Borders_[date].xml` or ENTSO-E Transparency Platform

| Field Name | Data Type | Description | Use in Features | Missing Value Strategy |
|------------|-----------|-------------|-----------------|----------------------|
| `border_id` | String | Non-Core border (e.g., "FR-UK", "FR-ES") | Border tracking | **REQUIRED** |
| `timestamp` | Datetime | Delivery hour | Time index | **REQUIRED** |
| `atc_forward` | Float (MW) | Available Transfer Capacity (forward direction) | Loop flow driver | 0.0 |
| `atc_backward` | Float (MW) | Available Transfer Capacity (backward direction) | Loop flow driver | 0.0 |

**Description:**
Available Transfer Capacity on borders connecting Core to non-Core regions. These affect loop flows through Core and impact Core CNEC constraints.

**Why This Matters:**
Large flows on external borders create loop flows through Core:
- **FR-UK flows** affect FR-BE, FR-DE capacities via loop flows
- **Swiss transit** (FR-CH-AT-DE) impacts Core CNECs significantly
- **Nordic flows** through DE-DK affect German internal CNECs
- **Italian flows** through AT-IT affect Austrian CNECs

**Key Non-Core Borders to Collect (~14 borders):**
1. **FR-UK** (IFA, ElecLink, IFA2 interconnectors) - Major loop flow driver
2. **FR-ES** (Pyrenees corridor)
3. **FR-CH** (Alpine corridor to Switzerland)
4. **DE-CH** (Basel-Laufenburg)
5. **AT-CH** (Alpine corridor)
6. **DE-DK** (to Nordic region)
7. **PL-SE** (Baltic to Nordic)
8. **PL-LT** (Baltic connection)
9. **AT-SI** (SEE gateway)
10. **AT-IT** (Brenner Pass)
11. **HU-RO** (SEE connection)
12. **HU-RS** (Balkans)
13. **HR-RS** (Balkans)
14. **SI-IT** (SEE to Italy)

**Collection Method:**
1. **JAO Publication Tool:** Core_ATC_External_Borders
2. **ENTSO-E Transparency Platform:** Fallback if JAO incomplete

**Collection Priority:** DAY 1 AFTERNOON (after core data)

**Storage Schema:**
```python
atc_external_schema = {
    'timestamp': pl.Datetime,
    'border_id': pl.Utf8,
    'atc_forward': pl.Float32,
    'atc_backward': pl.Float32
}
```

**Expected File Size:** ~120-160 MB for 24 months × 14 borders

**ENTSO-E API Collection (if needed):**
```python
from entsoe import EntsoePandasClient

non_core_borders = [
    ('FR', 'UK'), ('FR', 'ES'), ('FR', 'CH'),
    ('DE', 'CH'), ('DE', 'DK'),
    ('AT', 'CH'), ('AT', 'IT'),
    ('PL', 'SE'), ('PL', 'LT')
]

for zone1, zone2 in non_core_borders:
    atc_data = client.query_offered_capacity(
        country_code_from=zone1,
        country_code_to=zone2,
        start=start_date,
        end=end_date
    )
```

---

## 3. Data Cleaning Procedures

### 3.1 Missing Value Handling

**Priority Order:**
1. **Forward-fill** (for continuous series with gradual changes)
2. **Zero-fill** (for event-based fields where absence means "not active")
3. **Interpolation** (for weather-related smooth series)
4. **Drop** (only if >30% missing in critical fields)

**Field-Specific Strategies:**

| Field | Strategy | Justification |
|-------|----------|---------------|
| `ram_after` | Forward-fill (max 2 hours), then linear interpolation | Capacity changes gradually |
| `presolved` | Zero-fill → False | Missing = not binding |
| `shadow_price` | Zero-fill | Missing = no congestion cost |
| `ptdf_value` | Zero-fill | Missing = no sensitivity |
| `fmax` | **NO FILL - MUST HAVE** | Critical for normalization |
| `flow_fb` | Zero-fill | Missing = no flow |
| `cnec_name` | Forward-fill | Descriptive only |

**Implementation:**
```python
def clean_jao_data(df: pl.DataFrame) -> pl.DataFrame:
    """Clean JAO data with field-specific strategies"""
    
    # 1. Handle critical fields (fail if missing)
    critical_fields = ['timestamp', 'cnec_id', 'fmax']
    for field in critical_fields:
        if df[field].null_count() > 0:
            raise ValueError(f"Critical field {field} has missing values")
    
    # 2. Forward-fill continuous series
    df = df.with_columns([
        pl.col('ram_after').fill_null(strategy='forward').fill_null(strategy='backward'),
        pl.col('ram_before').fill_null(strategy='forward').fill_null(strategy='backward'),
        pl.col('cnec_name').fill_null(strategy='forward')
    ])
    
    # 3. Zero-fill event indicators
    df = df.with_columns([
        pl.col('presolved').fill_null(False),
        pl.col('shadow_price').fill_null(0.0),
        pl.col('flow_fb').fill_null(0.0),
        pl.col('remedial_actions_applied').fill_null(False)
    ])
    
    # 4. Linear interpolation for remaining RAM gaps (max 2 hours)
    df = df.with_columns([
        pl.col('ram_after').interpolate(method='linear')
    ])
    
    # 5. Fill contingency with "basecase" if missing
    df = df.with_columns([
        pl.col('contingency').fill_null('basecase')
    ])
    
    return df
```

### 3.2 Outlier Detection & Treatment

**RAM Outliers:**
```python
def detect_ram_outliers(df: pl.DataFrame) -> pl.DataFrame:
    """Flag and clip RAM outliers"""
    
    # 1. Physical constraints
    df = df.with_columns([
        # RAM cannot exceed Fmax
        pl.when(pl.col('ram_after') > pl.col('fmax'))
          .then(pl.col('fmax'))
          .otherwise(pl.col('ram_after'))
          .alias('ram_after'),
        
        # RAM cannot be negative (clip to 0)
        pl.when(pl.col('ram_after') < 0)
          .then(0.0)
          .otherwise(pl.col('ram_after'))
          .alias('ram_after')
    ])
    
    # 2. Statistical outliers (sudden unrealistic jumps)
    # Flag if RAM drops >80% in 1 hour (likely data error)
    df = df.with_columns([
        (pl.col('ram_after').diff() / pl.col('ram_after').shift(1) < -0.8)
        .fill_null(False)
        .alias('outlier_sudden_drop')
    ])
    
    # 3. Replace flagged outliers with interpolation
    df = df.with_columns([
        pl.when(pl.col('outlier_sudden_drop'))
          .then(None)
          .otherwise(pl.col('ram_after'))
          .alias('ram_after')
    ]).with_columns([
        pl.col('ram_after').interpolate()
    ])
    
    return df.drop('outlier_sudden_drop')
```

**PTDF Outliers:**
```python
def clean_ptdf_outliers(ptdf_matrix: np.ndarray) -> np.ndarray:
    """Clean PTDF values to physical bounds"""
    
    # PTDFs theoretically in [-1, 1] but can be slightly outside due to rounding
    # Clip to [-1.5, 1.5] to catch errors while allowing small overruns
    ptdf_matrix = np.clip(ptdf_matrix, -1.5, 1.5)
    
    # Replace any NaN/Inf with 0 (no sensitivity)
    ptdf_matrix = np.nan_to_num(ptdf_matrix, nan=0.0, posinf=0.0, neginf=0.0)
    
    return ptdf_matrix
```

**Shadow Price Outliers:**
```python
def clean_shadow_prices(df: pl.DataFrame) -> pl.DataFrame:
    """Handle extreme shadow prices"""
    
    # Shadow prices above €500/MW are rare but possible during extreme scarcity
    # Cap at €1000/MW to prevent contamination (99.9th percentile historically)
    df = df.with_columns([
        pl.when(pl.col('shadow_price') > 1000)
          .then(1000)
          .otherwise(pl.col('shadow_price'))
          .alias('shadow_price')
    ])
    
    return df
```

### 3.3 Timestamp Alignment

**Challenge:** JAO publishes data for "delivery day D+1" on "business day D"

**Solution:**
```python
def align_jao_timestamps(df: pl.DataFrame) -> pl.DataFrame:
    """Convert business day to delivery hour timestamps"""
    
    # JAO format: business_day='2025-10-28', delivery_hour=1-24
    # Convert to: timestamp='2025-10-29 00:00' to '2025-10-29 23:00' (UTC)
    
    df = df.with_columns([
        # Delivery timestamp = business_day + 1 day + (delivery_hour - 1)
        (pl.col('business_day') + pl.duration(days=1) + 
         pl.duration(hours=pl.col('delivery_hour') - 1))
        .alias('timestamp')
    ])
    
    # Convert from CET/CEST to UTC for consistency
    df = df.with_columns([
        pl.col('timestamp').dt.convert_time_zone('UTC')
    ])
    
    return df
```

### 3.4 Duplicate Handling

**Sources of Duplicates:**
1. D-2 and D-1 PTDF updates (keep D-1 only)
2. Corrected publications (keep latest by publication time)
3. Intraday updates (out of scope for day-ahead forecasting)

**Deduplication Strategy:**
```python
def deduplicate_jao_data(df: pl.DataFrame) -> pl.DataFrame:
    """Remove duplicate records, keeping most recent version"""
    
    # For PTDF data: keep D-1 version
    if 'version' in df.columns:
        df = df.filter(pl.col('version') == 'D-1')
    
    # For all data: keep latest publication time per (timestamp, cnec_id)
    df = (df
          .sort('publication_time', descending=True)
          .unique(subset=['timestamp', 'cnec_id'], keep='first'))
    
    return df
```

---

## 4. CNEC Treatment

### 4.1 CNEC Selection Strategy

**Goal:** Reduce from **~2,000 CNECs published daily by TSOs** to **Top 200 most impactful CNECs**

**Two-Tier Approach:**
- **Tier 1 (Top 50 CNECs):** Full feature detail (5 features each = 250 features)
- **Tier 2 (Next 150 CNECs):** Selective features (2 features each = 300 features)
- **Total:** 200 CNECs tracked

**Selection Criteria:**
1. **Binding Frequency** (40% weight): How often was CNEC active?
2. **Economic Impact** (30% weight): Average shadow price when binding
3. **RAM Utilization** (20% weight): How close to limit (low RAM)?
4. **Geographic Coverage** (10% weight): Ensure all borders represented

**Implementation:**
```python
def select_top_cnecs(df: pl.DataFrame, n_cnecs: int = 200) -> dict[str, list[str]]:
    """
    Select top 200 most impactful CNECs from ~2,000 published daily
    Returns: {'tier1': list of 50 CNECs, 'tier2': list of 150 CNECs}
    """
    
    cnec_impact = df.groupby('cnec_id').agg([
        # Binding frequency (times active / total hours)
        (pl.col('presolved').sum() / pl.col('presolved').count())
        .alias('binding_freq'),
        
        # Average shadow price when binding
        pl.col('shadow_price').filter(pl.col('presolved')).mean()
        .alias('avg_shadow_price'),
        
        # RAM utilization (% of hours below 30% of Fmax)
        ((pl.col('ram_after') < 0.3 * pl.col('fmax')).sum() / 
         pl.col('ram_after').count())
        .alias('low_ram_freq'),
        
        # Days appeared (consistency metric)
        pl.col('cnec_id').count().alias('days_appeared'),
        
        # Geographic zone (parse from CNEC ID)
        pl.col('tso').first().alias('tso')
    ])
    
    # Calculate composite impact score
    cnec_impact = cnec_impact.with_columns([
        (0.40 * pl.col('binding_freq') +
         0.30 * (pl.col('avg_shadow_price') / 100) +  # Normalize to [0,1]
         0.20 * pl.col('low_ram_freq') +
         0.10 * (pl.col('days_appeared') / 365))  # Consistency bonus
        .alias('impact_score')
    ])
    
    # Select top N, ensuring geographic diversity
    top_cnecs = []
    
    # First, get top 10 per major bidding zone border (ensures coverage)
    for border in ['DE_FR', 'DE_NL', 'DE_CZ', 'FR_BE', 'AT_CZ', 'DE_AT', 
                   'FR_ES', 'AT_IT', 'DE_PL', 'BE_NL']:
        border_cnecs = (cnec_impact
                       .filter(pl.col('cnec_id').str.contains(border))
                       .sort('impact_score', descending=True)
                       .head(10))
        top_cnecs.extend(border_cnecs['cnec_id'].to_list())
    
    # Remove duplicates (some CNECs may match multiple borders)
    top_cnecs = list(set(top_cnecs))
    
    # Then add remaining highest-impact CNECs to reach n_cnecs
    remaining = (cnec_impact
                .filter(~pl.col('cnec_id').is_in(top_cnecs))
                .sort('impact_score', descending=True)
                .head(n_cnecs - len(top_cnecs)))
    top_cnecs.extend(remaining['cnec_id'].to_list())
    
    # Split into two tiers
    tier1_cnecs = top_cnecs[:50]   # Top 50 get full feature detail
    tier2_cnecs = top_cnecs[50:200]  # Next 150 get selective features
    
    return {
        'tier1': tier1_cnecs,
        'tier2': tier2_cnecs,
        'all': top_cnecs[:200]
    }
```

**Why 200 CNECs?**
- From ~2,000 published daily, most are rarely binding or have minimal economic impact
- Top 200 captures >95% of all binding events and congestion costs
- Manageable feature space while preserving critical network information
- Two-tier approach balances detail vs. dimensionality

### 4.2 CNEC Masking Strategy

**Problem:** Not all CNECs are published every day (only those considered relevant by TSOs)

**Solution:** Create a "Master CNEC Set" with masking

```python
def create_cnec_master_set(df: pl.DataFrame, top_cnecs: list[str]) -> pl.DataFrame:
    """Create complete CNEC × timestamp matrix with masking"""
    
    # 1. Create complete timestamp × CNEC grid
    all_timestamps = df.select('timestamp').unique().sort('timestamp')
    cnec_template = pl.DataFrame({'cnec_id': top_cnecs})
    
    # Cartesian product: all timestamps × all CNECs
    complete_grid = all_timestamps.join(cnec_template, how='cross')
    
    # 2. Left join with actual data
    complete_data = complete_grid.join(
        df.select(['timestamp', 'cnec_id', 'ram_after', 'presolved', 
                  'shadow_price', 'fmax']),
        on=['timestamp', 'cnec_id'],
        how='left'
    )
    
    # 3. Add masking indicator
    complete_data = complete_data.with_columns([
        # Mask = 1 if CNEC was published (data available)
        # Mask = 0 if CNEC not published (implicitly unconstrained)
        (~pl.col('ram_after').is_null()).cast(pl.Int8).alias('cnec_mask')
    ])
    
    # 4. Fill missing values according to strategy
    complete_data = complete_data.with_columns([
        # If not published, assume unconstrained:
        # - RAM = Fmax (maximum margin)
        # - presolved = False (not binding)
        # - shadow_price = 0 (no congestion)
        pl.col('ram_after').fill_null(pl.col('fmax')),
        pl.col('presolved').fill_null(False),
        pl.col('shadow_price').fill_null(0.0)
    ])
    
    return complete_data
```

**Resulting Schema:**
```
timestamp            cnec_id          ram_after  presolved  shadow_price  cnec_mask  fmax
2024-10-01 00:00    DE_CZ_TIE_001     450.2     True       12.5          1          800
2024-10-01 00:00    DE_FR_LINE_005    800.0     False      0.0           0          800   # Not published
2024-10-01 01:00    DE_CZ_TIE_001     432.1     True       15.2          1          800
...
```

### 4.3 CNEC Feature Derivation

**From master CNEC set, derive:**

```python
def engineer_cnec_features(df: pl.DataFrame) -> pl.DataFrame:
    """Create CNEC-based features for forecasting"""
    
    df = df.with_columns([
        # 1. Margin ratio (normalized RAM)
        (pl.col('ram_after') / pl.col('fmax')).alias('margin_ratio'),
        
        # 2. Binding frequency (7-day rolling)
        pl.col('presolved').cast(pl.Int8).rolling_mean(window_size=168)
        .over('cnec_id').alias('binding_freq_7d'),
        
        # 3. Binding frequency (30-day rolling)
        pl.col('presolved').cast(pl.Int8).rolling_mean(window_size=720)
        .over('cnec_id').alias('binding_freq_30d'),
        
        # 4. MinRAM compliance
        (pl.col('ram_after') < 0.7 * pl.col('fmax'))
        .cast(pl.Int8).alias('below_minram'),
        
        # 5. RAM volatility (7-day rolling std)
        pl.col('ram_after').rolling_std(window_size=168)
        .over('cnec_id').alias('ram_volatility_7d'),
        
        # 6. Shadow price volatility
        pl.col('shadow_price').rolling_std(window_size=168)
        .over('cnec_id').alias('shadow_price_volatility_7d'),
        
        # 7. CNEC criticality score
        (1 - pl.col('margin_ratio')).alias('criticality'),
        
        # 8. Sudden RAM drops (binary flag)
        ((pl.col('ram_after') - pl.col('ram_after').shift(1)) < -0.2 * pl.col('fmax'))
        .cast(pl.Int8).alias('sudden_ram_drop')
    ])
    
    return df
```

---

## 5. PTDF Treatment - Hybrid Approach

### 5.1 Strategy: Preserve Causality for Critical CNECs

**Challenge:** PTDF matrix contains critical network physics but is high-dimensional
- 200 CNECs × 12 zones × 17,520 hours = ~42 million values
- PTDFs encode how zone injections affect each CNEC (network sensitivity)
- **Critical requirement:** Preserve CNEC-specific causality chain:
  - `outage_active_cnec_X` → network sensitivity (PTDF) → `presolved_cnec_X`

**Solution: Two-Tier Hybrid Approach**

#### **Tier 1 (Top 50 CNECs): Individual PTDF Features**
**Preserve all 12 zone sensitivities for each of the 50 most critical CNECs**
- Result: 50 CNECs × 12 zones = **600 individual PTDF features**
- Rationale: These are most impactful CNECs - model needs full network physics
- Enables learning: "When `outage_active_cnec_42` = 1 AND high DE_LU injection (via `ptdf_cnec_42_DE_LU` sensitivity), THEN `presolved_cnec_42` likely = 1"

#### **Tier 2 (Next 150 CNECs): Border-Level PTDF Aggregates**
**Aggregate PTDF sensitivities by border-zone pairs**
- Result: 10 borders × 12 zones = **120 aggregate PTDF features**
- Rationale: Captures regional network patterns without full individual resolution
- Preserves interpretability: "How sensitive are DE-CZ tier-2 CNECs to German generation?"
- Still allows causal learning: `outage_active_cnec_tier2` → `avg_ptdf_border` → `presolved_cnec_tier2`

**Total PTDF Features: 720 (600 individual + 120 aggregate)**

**Why This Approach?**
1. ✅ **Preserves CNEC-specific causality for top 50** - most critical constraints
2. ✅ **Avoids PCA mixing** - no loss of CNEC identification
3. ✅ **Interpretable** - can explain which zones affect which borders
4. ✅ **Dimensionality reduction** - 1,800 tier-2 values → 120 features (15:1)
5. ✅ **Maintains geographic structure** - DE-CZ separate from FR-BE

### 5.2 Implementation: Top 50 Individual PTDFs

```python
def extract_top50_ptdfs(ptdf_matrix: np.ndarray, 
                        top_50_cnec_ids: list[str],
                        all_cnec_ids: list[str],
                        zones: list[str]) -> pl.DataFrame:
    """
    Extract individual PTDF values for top 50 CNECs
    
    Args:
        ptdf_matrix: Shape (n_timestamps, n_cnecs, n_zones)
        top_50_cnec_ids: List of 50 most critical CNEC identifiers
        all_cnec_ids: Full list of CNEC IDs matching matrix dimension
        zones: List of 12 Core zone identifiers ['DE_LU', 'FR', 'BE', 'NL', ...]
        
    Returns:
        DataFrame with 600 PTDF features (50 CNECs × 12 zones)
    """
    
    # Find indices of top 50 CNECs in the full matrix
    top_50_indices = [all_cnec_ids.index(cnec) for cnec in top_50_cnec_ids]
    
    # Extract PTDF values for top 50 CNECs
    # Shape: (n_timestamps, 50, 12)
    top_50_ptdfs = ptdf_matrix[:, top_50_indices, :]
    
    # Reshape to flat features: (n_timestamps, 600)
    n_timestamps = top_50_ptdfs.shape[0]
    features_dict = {}
    
    for cnec_idx, cnec_id in enumerate(top_50_cnec_ids):
        for zone_idx, zone in enumerate(zones):
            feature_name = f'ptdf_cnec_{cnec_id}_{zone}'
            features_dict[feature_name] = top_50_ptdfs[:, cnec_idx, zone_idx]
    
    print(f"✓ Extracted {len(features_dict)} individual PTDF features for top 50 CNECs")
    return pl.DataFrame(features_dict)
```

### 5.3 Implementation: Tier-2 Border Aggregates

```python
def aggregate_tier2_ptdfs_by_border(ptdf_matrix: np.ndarray,
                                    tier2_cnec_ids: list[str],
                                    all_cnec_ids: list[str],
                                    zones: list[str]) -> pl.DataFrame:
    """
    Aggregate PTDF sensitivities for tier-2 CNECs by border-zone pairs
    
    Args:
        ptdf_matrix: Shape (n_timestamps, n_cnecs, n_zones)
        tier2_cnec_ids: List of 150 tier-2 CNEC identifiers
        all_cnec_ids: Full list of CNEC IDs
        zones: List of 12 Core zone identifiers
        
    Returns:
        DataFrame with 120 features (10 borders × 12 zones)
    """
    
    # Define major borders
    major_borders = ['DE_FR', 'DE_NL', 'DE_CZ', 'FR_BE', 'AT_CZ', 
                     'DE_AT', 'BE_NL', 'AT_IT', 'DE_PL', 'CZ_PL']
    
    # Find indices of tier-2 CNECs
    tier2_indices = [all_cnec_ids.index(cnec) for cnec in tier2_cnec_ids]
    
    # Extract tier-2 PTDF subset
    tier2_ptdfs = ptdf_matrix[:, tier2_indices, :]  # (n_timestamps, 150, 12)
    
    features_dict = {}
    
    for border in major_borders:
        # Find tier-2 CNECs belonging to this border
        border_cnec_indices = [
            i for i, cnec_id in enumerate(tier2_cnec_ids)
            if border.replace('_', '').lower() in cnec_id.lower()
        ]
        
        if len(border_cnec_indices) == 0:
            # No tier-2 CNECs for this border - use zeros
            for zone in zones:
                features_dict[f'avg_ptdf_{border}_{zone}_tier2'] = np.zeros(tier2_ptdfs.shape[0])
            continue
        
        # Average PTDF across all tier-2 CNECs on this border
        for zone_idx, zone in enumerate(zones):
            border_zone_ptdfs = tier2_ptdfs[:, border_cnec_indices, zone_idx]
            avg_ptdf = np.mean(border_zone_ptdfs, axis=1)
            features_dict[f'avg_ptdf_{border}_{zone}_tier2'] = avg_ptdf
    
    print(f"✓ Aggregated {len(features_dict)} border-zone PTDF features for tier-2")
    return pl.DataFrame(features_dict)
```

### 5.4 Complete PTDF Pipeline

```python
def prepare_ptdf_features(ptdf_matrix: np.ndarray,
                          top_50_cnecs: list[str],
                          tier2_cnecs: list[str],
                          all_cnec_ids: list[str],
                          zones: list[str]) -> pl.DataFrame:
    """
    Complete PTDF feature engineering pipeline
    
    Returns:
        DataFrame with 720 PTDF features total:
        - 600 individual features (top 50 CNECs × 12 zones)
        - 120 aggregate features (10 borders × 12 zones for tier-2)
    """
    
    # 1. Extract individual PTDFs for top 50
    top50_features = extract_top50_ptdfs(
        ptdf_matrix, top_50_cnecs, all_cnec_ids, zones
    )
    
    # 2. Aggregate tier-2 PTDFs by border
    tier2_features = aggregate_tier2_ptdfs_by_border(
        ptdf_matrix, tier2_cnecs, all_cnec_ids, zones
    )
    
    # 3. Combine
    all_ptdf_features = pl.concat([top50_features, tier2_features], how='horizontal')
    
    print(f"\n✓ PTDF Features Generated:")
    print(f"  Top 50 individual: {top50_features.shape[1]} features")
    print(f"  Tier-2 aggregated: {tier2_features.shape[1]} features")
    print(f"  Total PTDF features: {all_ptdf_features.shape[1]}")
    
    return all_ptdf_features
```

### 5.5 PTDF Feature Validation

```python
def validate_ptdf_features(ptdf_features: pl.DataFrame) -> None:
    """Validate PTDF feature quality"""
    
    # 1. Check for valid range (PTDFs should be in [-1, 1])
    outliers = []
    for col in ptdf_features.columns:
        if col.startswith('ptdf_') or col.startswith('avg_ptdf_'):
            values = ptdf_features[col]
            min_val, max_val = values.min(), values.max()
            
            if min_val < -1.5 or max_val > 1.5:
                outliers.append(f"{col}: [{min_val:.3f}, {max_val:.3f}]")
    
    if outliers:
        print(f"âš  WARNING: {len(outliers)} PTDF features outside expected [-1, 1] range")
        for out in outliers[:5]:  # Show first 5
            print(f"  {out}")
    
    # 2. Check for constant features (no variance)
    constant_features = []
    for col in ptdf_features.columns:
        if col.startswith('ptdf_') or col.startswith('avg_ptdf_'):
            if ptdf_features[col].std() < 1e-6:
                constant_features.append(col)
    
    if constant_features:
        print(f"âš  WARNING: {len(constant_features)} PTDF features have near-zero variance")
    
    # 3. Summary statistics
    print(f"\n✓ PTDF Feature Validation Complete:")
    print(f"  Features in valid range: {len(ptdf_features.columns) - len(outliers)}")
    print(f"  Features with variance: {len(ptdf_features.columns) - len(constant_features)}")
```


---

## 6. RAM Treatment

### 6.1 RAM Normalization

**Challenge:** Absolute RAM values vary widely across CNECs (50 MW to 2000 MW)

**Solution:** Normalize to margin ratio

```python
def normalize_ram_values(df: pl.DataFrame) -> pl.DataFrame:
    """Normalize RAM to comparable scale"""
    
    df = df.with_columns([
        # 1. Margin ratio: RAM / Fmax
        (pl.col('ram_after') / pl.col('fmax')).alias('margin_ratio'),
        
        # 2. MinRAM compliance ratio: RAM / (0.7 × Fmax)
        (pl.col('ram_after') / (0.7 * pl.col('fmax'))).alias('minram_compliance'),
        
        # 3. Percentile within CNEC's historical distribution
        pl.col('ram_after').rank(method='average').over('cnec_id')
        .alias('ram_percentile')
    ])
    
    # Cap margin_ratio at 1.0 (cannot exceed Fmax)
    df = df.with_columns([
        pl.when(pl.col('margin_ratio') > 1.0)
          .then(1.0)
          .otherwise(pl.col('margin_ratio'))
          .alias('margin_ratio')
    ])
    
    return df
```

### 6.2 RAM Time Series Features

```python
def engineer_ram_features(df: pl.DataFrame) -> pl.DataFrame:
    """Create rolling window features from RAM values"""
    
    df = df.with_columns([
        # 1. Moving averages
        pl.col('ram_after').rolling_mean(window_size=24).alias('ram_ma_24h'),
        pl.col('ram_after').rolling_mean(window_size=168).alias('ram_ma_7d'),
        pl.col('ram_after').rolling_mean(window_size=720).alias('ram_ma_30d'),
        
        # 2. Volatility measures
        pl.col('ram_after').rolling_std(window_size=168).alias('ram_std_7d'),
        pl.col('ram_after').rolling_std(window_size=720).alias('ram_std_30d'),
        
        # 3. Percentiles (vs 90-day history)
        pl.col('ram_after')
          .rolling_quantile(quantile=0.1, window_size=2160)
          .alias('ram_p10_90d'),
        pl.col('ram_after')
          .rolling_quantile(quantile=0.5, window_size=2160)
          .alias('ram_median_90d'),
        
        # 4. Rate of change
        (pl.col('ram_after').diff(1) / pl.col('ram_after').shift(1))
        .alias('ram_pct_change_1h'),
        (pl.col('ram_after').diff(24) / pl.col('ram_after').shift(24))
        .alias('ram_pct_change_24h'),
        
        # 5. Binary indicators
        (pl.col('ram_after') < 0.3 * pl.col('fmax'))
        .cast(pl.Int8).alias('low_ram_flag'),
        
        ((pl.col('ram_after') - pl.col('ram_after').shift(1)) < -0.2 * pl.col('fmax'))
        .cast(pl.Int8).alias('sudden_drop_flag'),
        
        # 6. MinRAM violation counter (7-day window)
        (pl.col('ram_after') < 0.7 * pl.col('fmax'))
        .cast(pl.Int8)
        .rolling_sum(window_size=168)
        .alias('minram_violations_7d')
    ])
    
    return df
```

### 6.3 Cross-Border RAM Aggregation

**Create system-level RAM features:**

```python
def aggregate_ram_system_wide(df: pl.DataFrame) -> pl.DataFrame:
    """Aggregate RAM across all CNECs to system-level features"""
    
    system_features = df.groupby('timestamp').agg([
        # 1. Average margin across all CNECs
        pl.col('margin_ratio').mean().alias('system_avg_margin'),
        
        # 2. Minimum margin (most constrained CNEC)
        pl.col('margin_ratio').min().alias('system_min_margin'),
        
        # 3. Count of binding CNECs
        pl.col('presolved').sum().alias('n_binding_cnecs'),
        
        # 4. Count of CNECs below minRAM
        (pl.col('ram_after') < 0.7 * pl.col('fmax')).sum()
        .alias('n_cnecs_below_minram'),
        
        # 5. Standard deviation of margins (uniformity)
        pl.col('margin_ratio').std().alias('margin_std'),
        
        # 6. Total economic cost (sum of shadow prices)
        pl.col('shadow_price').sum().alias('total_congestion_cost'),
        
        # 7. Max shadow price
        pl.col('shadow_price').max().alias('max_shadow_price')
    ])
    
    return system_features
```

---

## 7. Shadow Prices Treatment

### 7.1 Shadow Price Features

```python
def engineer_shadow_price_features(df: pl.DataFrame) -> pl.DataFrame:
    """Create features from shadow prices (economic signals)"""
    
    df = df.with_columns([
        # 1. Rolling statistics
        pl.col('shadow_price').rolling_mean(window_size=24)
        .alias('shadow_price_ma_24h'),
        
        pl.col('shadow_price').rolling_max(window_size=24)
        .alias('shadow_price_max_24h'),
        
        pl.col('shadow_price').rolling_std(window_size=168)
        .alias('shadow_price_volatility_7d'),
        
        # 2. Binary indicators
        (pl.col('shadow_price') > 0).cast(pl.Int8)
        .alias('has_congestion_cost'),
        
        (pl.col('shadow_price') > 50).cast(pl.Int8)
        .alias('high_congestion_flag'),  # €50/MW threshold
        
        # 3. Economic stress indicator (count of expensive hours in 7d)
        (pl.col('shadow_price') > 50).cast(pl.Int8)
        .rolling_sum(window_size=168)
        .alias('expensive_hours_7d'),
        
        # 4. Shadow price persistence (how long has it been >0?)
        # Create groups of consecutive non-zero shadow prices
        ((pl.col('shadow_price') > 0) != (pl.col('shadow_price').shift(1) > 0))
        .cum_sum()
        .alias('shadow_price_regime'),
        
    ])
    
    # 5. Duration in current regime
    df = df.with_columns([
        pl.col('shadow_price_regime')
        .rank(method='dense').over('shadow_price_regime')
        .alias('hours_in_regime')
    ])
    
    return df
```

---

## 8. Feature Engineering Pipeline

### 8.1 Complete Feature Matrix Construction

**Final feature set: ~1,060 features (Option A Architecture)**
- **Historical Context:** 730 features (what happened in past 21 days)
- **Future Covariates:** 280 features (what we know will happen in next 14 days)
- **System-Level:** 50 features (real-time aggregates)

**Architecture Rationale:**
- **Top 50 CNECs:** Full detail (5 metrics each = 250 features)
  - Most impactful CNECs get complete representation
- **Tier-2 150 CNECs:** Selective detail (300 features)
  - Binary indicators: `presolved` (binding) + `outage_active` (150 + 150 = 300 features)
  - Aggregated metrics: RAM, shadow prices by border (30 features)
  - Preserves high-signal discrete events while reducing continuous redundancy
- **Supporting Features:** 380 features
  - PTDF patterns, border capacities, weather, temporal, interactions

```python
class JAOFeatureEngineer:
    """
    Complete JAO feature engineering pipeline - Option A Architecture
    
    Architecture:
    - Top 50 CNECs: Full detail (5 metrics × 50 = 250 features)
    - Tier-2 150 CNECs: Selective (presolved + outage_active = 300 features)
    - Tier-2 aggregated: Border-level RAM/shadow prices (30 features)
    - Supporting: PTDF, borders, system, temporal, weather (150 features)
    
    Total: ~730 historical features + ~280 future covariates
    
    Inputs: Raw JAO data (CNECs, PTDFs, RAMs, shadow prices) + ENTSO-E outages
    Outputs: Engineered feature matrix (512h × 730 features) + 
             Future covariates (336h × 280 features)
    """
    
    def __init__(self, top_n_cnecs: int = 50, tier2_n_cnecs: int = 150, 
                 ptdf_components: int = 10):
        self.top_n_cnecs = top_n_cnecs
        self.tier2_n_cnecs = tier2_n_cnecs
        self.total_cnecs = top_n_cnecs + tier2_n_cnecs  # 200 total
        self.ptdf_components = ptdf_components
        self.pca_model = None
        self.scaler = None
        self.top_cnecs = None
        self.tier2_cnecs = None
        
    def fit(self, historical_data: dict):
        """
        Fit on 12-month historical data to establish baselines
        
        Args:
            historical_data: {
                'cnecs': pl.DataFrame,
                'ptdfs': np.ndarray,
                'rams': pl.DataFrame,
                'shadow_prices': pl.DataFrame,
                'outages': pl.DataFrame (from ENTSO-E via EIC matching)
            }
        """
        
        print("Fitting JAO feature engineer on historical data...")
        
        # 1. Select top 200 CNECs (50 + 150)
        print(f"  - Selecting top {self.total_cnecs} CNECs...")
        all_selected = select_top_cnecs(
            historical_data['cnecs'], 
            n_cnecs=self.total_cnecs
        )
        self.top_cnecs = all_selected[:self.top_n_cnecs]
        self.tier2_cnecs = all_selected[self.top_n_cnecs:]
        
        print(f"    Top 50: {self.top_cnecs[:3]}... (full detail)")
        print(f"    Tier-2 150: {self.tier2_cnecs[:3]}... (selective detail)")
        
        # 2. Engineer PTDF features (hybrid approach)
        print("  - Engineering PTDF features...")
        ptdf_compressed, self.pca_model, self.scaler = reduce_ptdf_dimensions(
            historical_data['ptdfs'], 
            n_components=self.ptdf_components
        )
        
        # 3. Calculate historical baselines (for percentiles, etc.)
        print("  - Computing historical baselines...")
        self.ram_baseline = historical_data['rams'].groupby('cnec_id').agg([
            pl.col('ram_after').mean().alias('ram_mean'),
            pl.col('ram_after').std().alias('ram_std'),
            pl.col('ram_after').quantile(0.1).alias('ram_p10'),
            pl.col('ram_after').quantile(0.9).alias('ram_p90')
        ])
        
        print("✓ Feature engineer fitted")
        
    def transform(self, 
                  data: dict, 
                  start_time: str, 
                  end_time: str) -> tuple[np.ndarray, np.ndarray]:
        """
        Transform JAO data to feature matrices
        
        Args:
            data: Same structure as fit()
            start_time: Start of context window (e.g., 21 days before prediction)
            end_time: End of context window (prediction time)
        
        Returns:
            historical_features: (n_hours, 730) array of historical context
            future_features: (n_hours_future, 280) array of future covariates
        """
        
        n_hours = len(pd.date_range(start_time, end_time, freq='H'))
        historical_features = np.zeros((n_hours, 730))
        
        print("Engineering historical features...")
        
        # Filter to time window
        cnec_data = (data['cnecs']
                    .filter(pl.col('timestamp').is_between(start_time, end_time)))
        
        outage_data = (data['outages']
                      .filter(pl.col('timestamp').is_between(start_time, end_time)))
        
        # === TOP 50 CNECs - FULL DETAIL (250 features) ===
        print("  - Top 50 CNECs (full detail)...")
        top50_data = cnec_data.filter(pl.col('cnec_id').is_in(self.top_cnecs))
        top50_outages = outage_data.filter(pl.col('cnec_id').is_in(self.top_cnecs))
        
        col_idx = 0
        for cnec_id in self.top_cnecs:
            cnec_series = top50_data.filter(pl.col('cnec_id') == cnec_id).sort('timestamp')
            cnec_outage = top50_outages.filter(pl.col('cnec_id') == cnec_id).sort('timestamp')
            
            # 5 metrics per CNEC
            historical_features[:, col_idx] = cnec_series['ram_after'].to_numpy()
            historical_features[:, col_idx + 1] = (cnec_series['ram_after'] / cnec_series['fmax']).to_numpy()
            historical_features[:, col_idx + 2] = cnec_series['presolved'].cast(pl.Int8).to_numpy()
            historical_features[:, col_idx + 3] = cnec_series['shadow_price'].to_numpy()
            historical_features[:, col_idx + 4] = cnec_outage['outage_active'].to_numpy()
            
            col_idx += 5
        
        # === TIER-2 150 CNECs - SELECTIVE DETAIL (300 features) ===
        print("  - Tier-2 150 CNECs (presolved + outage)...")
        tier2_data = cnec_data.filter(pl.col('cnec_id').is_in(self.tier2_cnecs))
        tier2_outages = outage_data.filter(pl.col('cnec_id').is_in(self.tier2_cnecs))
        
        # Presolved flags (150 features)
        for cnec_id in self.tier2_cnecs:
            cnec_series = tier2_data.filter(pl.col('cnec_id') == cnec_id).sort('timestamp')
            historical_features[:, col_idx] = cnec_series['presolved'].cast(pl.Int8).to_numpy()
            col_idx += 1
        
        # Outage flags (150 features)
        for cnec_id in self.tier2_cnecs:
            cnec_outage = tier2_outages.filter(pl.col('cnec_id') == cnec_id).sort('timestamp')
            historical_features[:, col_idx] = cnec_outage['outage_active'].to_numpy()
            col_idx += 1
        
        # === TIER-2 AGGREGATED METRICS (30 features) ===
        print("  - Tier-2 aggregated metrics by border...")
        borders = ['DE_FR', 'DE_NL', 'DE_CZ', 'DE_BE', 'FR_BE', 'AT_CZ', 
                  'DE_AT', 'CZ_SK', 'AT_HU', 'PL_CZ']
        
        for border in borders:
            # Get tier-2 CNECs for this border
            border_cnecs = [c for c in self.tier2_cnecs if border.replace('_', '') in c]
            
            if not border_cnecs:
                historical_features[:, col_idx:col_idx + 3] = 0
                col_idx += 3
                continue
            
            border_data = tier2_data.filter(pl.col('cnec_id').is_in(border_cnecs))
            
            # Aggregate per timestamp
            border_agg = border_data.groupby('timestamp').agg([
                pl.col('ram_after').mean().alias('avg_ram'),
                (pl.col('ram_after') / pl.col('fmax')).mean().alias('avg_margin'),
                pl.col('shadow_price').sum().alias('total_shadow_price')
            ]).sort('timestamp')
            
            historical_features[:, col_idx] = border_agg['avg_ram'].to_numpy()
            historical_features[:, col_idx + 1] = border_agg['avg_margin'].to_numpy()
            historical_features[:, col_idx + 2] = border_agg['total_shadow_price'].to_numpy()
            col_idx += 3
        
        # === PTDF PATTERNS (10 features) ===
        print("  - PTDF compression...")
        ptdf_subset = data['ptdfs'][start_time:end_time, :, :]
        ptdf_2d = ptdf_subset.reshape(len(ptdf_subset), -1)
        ptdf_scaled = self.scaler.transform(ptdf_2d)
        ptdf_features = self.pca_model.transform(ptdf_scaled)  # (n_hours, 10)
        historical_features[:, col_idx:col_idx + 10] = ptdf_features
        col_idx += 10
        
        # === BORDER CAPACITY HISTORICAL (20 features) ===
        print("  - Border capacities...")
        capacity_historical = data['entsoe']['crossborder_flows'][start_time:end_time]
        historical_features[:, col_idx:col_idx + 20] = capacity_historical
        col_idx += 20
        
        # === SYSTEM-LEVEL AGGREGATES (20 features) ===
        print("  - System-level aggregates...")
        system_features = aggregate_ram_system_wide(cnec_data).to_numpy()
        historical_features[:, col_idx:col_idx + 20] = system_features
        col_idx += 20
        
        # === TEMPORAL FEATURES (10 features) ===
        print("  - Temporal features...")
        timestamps = pd.date_range(start_time, end_time, freq='H')
        temporal = create_temporal_features(timestamps)
        historical_features[:, col_idx:col_idx + 10] = temporal
        col_idx += 10
        
        # === WEATHER FEATURES (50 features) ===
        print("  - Weather features...")
        weather = data['weather'][start_time:end_time]
        historical_features[:, col_idx:col_idx + 50] = weather
        col_idx += 50
        
        # === INTERACTION FEATURES (40 features) ===
        print("  - Interaction features...")
        interactions = create_interaction_features(
            cnec_data, weather, timestamps
        )
        historical_features[:, col_idx:col_idx + 40] = interactions
        col_idx += 40
        
        print(f"✓ Historical features: {historical_features.shape}")
        assert col_idx == 730, f"Expected 730 features, got {col_idx}"
        
        # === FUTURE COVARIATES ===
        future_features = self._create_future_covariates(data, end_time)
        
        return historical_features, future_features
    
    def _create_future_covariates(self, data: dict, prediction_start: str) -> np.ndarray:
        """Create future covariates for 14-day horizon"""
        
        prediction_end = pd.Timestamp(prediction_start) + pd.Timedelta(days=14)
        n_hours_future = 336  # 14 days × 24 hours
        future_features = np.zeros((n_hours_future, 280))
        
        print("Engineering future covariates...")
        
        col_idx = 0
        
        # Top 50 CNEC planned outages (50 features)
        for cnec_id in self.top_cnecs:
            planned_outages = data['outages'].filter(
                (pl.col('cnec_id') == cnec_id) &
                (pl.col('outage_type') == 'planned') &
                (pl.col('timestamp') >= prediction_start) &
                (pl.col('timestamp') < prediction_end)
            ).sort('timestamp')
            
            future_features[:, col_idx] = planned_outages['outage_active'].to_numpy()
            col_idx += 1
        
        # Tier-2 150 CNEC planned outages (150 features)
        for cnec_id in self.tier2_cnecs:
            planned_outages = data['outages'].filter(
                (pl.col('cnec_id') == cnec_id) &
                (pl.col('outage_type') == 'planned') &
                (pl.col('timestamp') >= prediction_start) &
                (pl.col('timestamp') < prediction_end)
            ).sort('timestamp')
            
            future_features[:, col_idx] = planned_outages['outage_active'].to_numpy()
            col_idx += 1
        
        # Weather forecasts (50 features)
        weather_forecast = data['weather_forecast'][prediction_start:prediction_end]
        future_features[:, col_idx:col_idx + 50] = weather_forecast
        col_idx += 50
        
        # Temporal (10 features)
        future_timestamps = pd.date_range(prediction_start, prediction_end, freq='H', inclusive='left')
        temporal = create_temporal_features(future_timestamps)
        future_features[:, col_idx:col_idx + 10] = temporal
        col_idx += 10
        
        # Border capacity adjustments (20 features)
        planned_ntc = data['entsoe']['planned_ntc'][prediction_start:prediction_end]
        future_features[:, col_idx:col_idx + 20] = planned_ntc
        col_idx += 20
        
        print(f"✓ Future covariates: {future_features.shape}")
        assert col_idx == 280, f"Expected 280 future features, got {col_idx}"
        
        return future_features
```

### 8.2 Master Feature List (Option A Architecture)

**Total: ~1,060 features (730 historical + 280 future + 50 real-time aggregates)**

#### **Historical Context Features (730 total)**

**Category 1: Top 50 CNECs - Full Detail (250 features)**
For each of the 50 most impactful CNECs:
- `ram_after_cnec_[ID]`: RAM value (MW)
- `margin_ratio_cnec_[ID]`: RAM / Fmax (0-1 normalized)
- `presolved_cnec_[ID]`: Binding status (1=binding, 0=not binding)
- `shadow_price_cnec_[ID]`: Congestion cost (€/MW)
- `outage_active_cnec_[ID]`: Outage status (1=under outage, 0=operational)

**Selection Criteria:**
```
Impact Score = 0.25×(appearance rate) + 0.30×(binding frequency) + 
               0.20×(economic impact) + 0.15×(RAM tightness) + 
               0.10×(geographic importance)
```

**Category 2: Tier-2 150 CNECs - Selective Detail (300 features)**

*Individual Binary Indicators (300 features):*
- `presolved_cnec_[ID]`: Binding status for each tier-2 CNEC (150 features)
  - Preserves constraint activation patterns
  - Allows model to learn which CNECs bind under which conditions
  
- `outage_active_cnec_[ID]`: Outage status for each tier-2 CNEC (150 features)
  - Preserves EIC matching benefit
  - Enables learning of outage → binding causality
  - Available as future covariate (planned outages known ahead)

*Aggregated Continuous Metrics (30 features):*
Grouped by border (10 borders × 3 metrics):
- `avg_ram_[BORDER]_tier2`: Average RAM for tier-2 CNECs on this border
- `avg_margin_ratio_[BORDER]_tier2`: Average margin ratio
- `total_shadow_price_[BORDER]_tier2`: Sum of shadow prices

Borders: DE_FR, DE_NL, DE_CZ, DE_BE, FR_BE, AT_CZ, DE_AT, CZ_SK, AT_HU, PL_CZ

**Category 3: PTDF Patterns (10 features)**
- `ptdf_pc1` through `ptdf_pc10`: Principal components
- Compressed from (200 CNECs × 12 zones = 2,400 raw values)
- Captures ~92% of variance in network sensitivities

**Category 4: Border Capacity Historical (20 features)**
- `capacity_hist_de_fr`, `capacity_hist_de_nl`, etc.
- One feature per FBMC border (~20 borders)
- Actual historical cross-border flow capacity from ENTSO-E

**Category 5: System-Level Aggregates (20 features)**
- `system_min_margin`: Tightest CNEC margin across all 200
- `n_binding_cnecs_total`: Count of all binding CNECs
- `n_binding_cnecs_top50`: Count of top-50 CNECs binding
- `n_binding_cnecs_tier2`: Count of tier-2 CNECs binding
- `margin_std`: Standard deviation of margins (uniformity indicator)
- `total_congestion_cost`: Sum of all shadow prices (€)
- `max_shadow_price`: Highest shadow price (€/MW)
- `avg_shadow_price_binding`: Average shadow price when CNECs bind
- `total_outage_mw_fbmc`: Total transmission capacity under outage
- `n_cnecs_with_outage`: Count of CNECs affected by outages
- `forced_outage_count`: Count of unplanned outages
- `outage_stress_index`: Composite metric (count × duration × forced_ratio)
- `critical_line_outage_count`: High-voltage (380kV) outages
- `outage_geographic_spread`: Number of unique borders affected
- Additional 6 features: criticality scores, violation counts, etc.

**Category 6: Temporal Features (10 features)**
- `hour_of_day`: 0-23
- `day_of_week`: 0-6 (Monday=0)
- `month`: 1-12
- `day_of_year`: 1-365
- `is_weekend`: Binary (1=Sat/Sun, 0=weekday)
- `is_peak_hour`: Binary (1=8am-8pm, 0=off-peak)
- `is_holiday_de`, `is_holiday_fr`, `is_holiday_be`, `is_holiday_nl`: Country-specific holidays

**Category 7: Weather Features (50 features)**
Key grid points (10-12 strategic locations) × 5 metrics:
- Temperature (2m above ground, °C)
- Wind speed at 10m and 100m (m/s)
- Wind direction at 100m (degrees)
- Solar radiation / GHI (W/m²)
- Cloud cover (%)

Grid points cover: German hubs, French nuclear regions, North Sea wind, Alpine corridor, Baltic connections, etc.

**Category 8: Interaction Features (40 features)**
Cross-feature combinations capturing domain knowledge:
- `high_wind_low_margin`: (wind > 20 m/s) × (margin < 0.3)
- `weekend_low_demand_pattern`: is_weekend × (demand < p30)
- `outage_binding_correlation`: Rolling correlation of outage presence with binding events
- `nuclear_low_wind_pattern`: (FR nuclear < 40 GW) × (wind < 10 m/s)
- `solar_peak_congestion`: (solar > 40 GW) × (hour = 12-14)
- Various other combinations (weather × capacity, temporal × binding, etc.)

#### **Future Covariates (280 features)**

**Category 9: Top 50 CNEC Planned Outages (50 features)**
- `planned_outage_cnec_[ID]_d[horizon]`: Binary indicator for D+1 to D+14
- Known with certainty (scheduled maintenance published by TSOs)
- From ENTSO-E A78 document type, filtered to status='scheduled'

**Category 10: Tier-2 150 CNEC Planned Outages (150 features)**
- `planned_outage_cnec_[ID]_d[horizon]`: Binary for each tier-2 CNEC
- Preserves full EIC matching benefit for future horizon
- High-value features (outages directly constrain capacity)

**Category 11: Weather Forecasts (50 features)**
- Same structure as historical weather (10-12 grid points × 5 metrics)
- OpenMeteo provides 14-day forecasts (updated daily)
- Includes: temperature, wind, solar radiation, cloud cover

**Category 12: Future Temporal (10 features)**
- Same temporal features projected for D+1 to D+14
- Known with certainty (calendar, holidays, hour/day patterns)

**Category 13: Border Capacity Adjustments (20 features)**
- `planned_ntc_[BORDER]_d1`: Day-ahead NTC publication per border
- TSOs publish Net Transfer Capacity (NTC) values D-1 for D-day
- Available via ENTSO-E Transparency Platform
- Provides official capacity forecasts (complementary to our model)

---

### Feature Engineering Sequence

**Step 1: Load Raw Data (Day 1)**
- JAO CNECs, PTDFs, RAMs, shadow prices (24 months)
- ENTSO-E outages via EIC matching
- ENTSO-E actual generation, load, cross-border flows
- OpenMeteo weather (historical + forecasts)

**Step 2: Preprocess (Day 1-2)**
- Clean missing values (field-specific strategies)
- Detect and clip outliers
- Align timestamps (CET/CEST → UTC)
- Deduplicate records

**Step 3: CNEC Selection (Day 2)**
- Analyze all ~2,000 CNECs over 24 months
- Rank by impact score
- Select top 200 (50 + 150)

**Step 4: Feature Engineering (Day 2)**
- Top 50: Extract 5 metrics each
- Tier-2: Extract presolved + outage_active individually
- Tier-2: Aggregate RAM/shadow prices by border
- PTDF: Extract individual features for top 50, aggregate for tier-2
- Create temporal, weather, interaction features

**Step 5: Quality Checks (Day 2)**
- Validate feature distributions
- Check for NaN/Inf values
- Verify feature variance (no zero-variance)
- Confirm temporal alignment

**Step 6: Save Feature Matrix (Day 2)**
```
data/processed/
├── features_historical_730.parquet  # (17520 hours × 730 features)
├── features_future_280.parquet      # (17520 hours × 280 future covariates)
├── feature_names.json               # Column name mapping
└── feature_metadata.json            # Descriptions, ranges, types
```

---

## 9. Quality Assurance

### 9.1 Data Validation Checks

```python
def validate_jao_data(df: pl.DataFrame) -> dict:
    """
    Run comprehensive validation checks on JAO data
    
    Returns: Dict of validation results
    """
    
    results = {
        'passed': True,
        'warnings': [],
        'errors': []
    }
    
    # 1. Check for critical missing values
    critical_fields = ['timestamp', 'cnec_id', 'fmax', 'ram_after']
    for field in critical_fields:
        missing_pct = df[field].null_count() / len(df) * 100
        if missing_pct > 0:
            results['errors'].append(
                f"Critical field '{field}' has {missing_pct:.2f}% missing values"
            )
            results['passed'] = False
    
    # 2. Check timestamp continuity (should be hourly)
    time_diffs = df['timestamp'].diff().dt.total_hours()
    non_hourly = (time_diffs != 1).sum()
    if non_hourly > 0:
        results['warnings'].append(
            f"Found {non_hourly} non-hourly gaps in timestamps"
        )
    
    # 3. Check RAM physical constraints
    invalid_ram = (df['ram_after'] > df['fmax']).sum()
    if invalid_ram > 0:
        results['errors'].append(
            f"Found {invalid_ram} records where RAM > Fmax (physically impossible)"
        )
        results['passed'] = False
    
    negative_ram = (df['ram_after'] < 0).sum()
    if negative_ram > 0:
        results['warnings'].append(
            f"Found {negative_ram} records with negative RAM (clipped to 0)"
        )
    
    # 4. Check PTDF bounds
    if 'ptdf_value' in df.columns:
        out_of_bounds = ((df['ptdf_value'] < -1.5) | (df['ptdf_value'] > 1.5)).sum()
        if out_of_bounds > 0:
            results['warnings'].append(
                f"Found {out_of_bounds} PTDF values outside [-1.5, 1.5] (clipped)"
            )
    
    # 5. Check shadow price reasonableness
    extreme_shadows = (df['shadow_price'] > 1000).sum()
    if extreme_shadows > 0:
        results['warnings'].append(
            f"Found {extreme_shadows} shadow prices > €1000/MW (check for outliers)"
        )
    
    # 6. Check for duplicate records
    duplicates = df.select(['timestamp', 'cnec_id']).is_duplicated().sum()
    if duplicates > 0:
        results['errors'].append(
            f"Found {duplicates} duplicate (timestamp, cnec_id) pairs"
        )
        results['passed'] = False
    
    # 7. Check data completeness by month
    monthly_counts = df.groupby(df['timestamp'].dt.month()).count()
    expected_hours_per_month = {1: 744, 2: 672, 3: 744, ...}  # Account for leap years
    for month, count in monthly_counts.items():
        expected = expected_hours_per_month.get(month, 720)
        if count < expected * 0.95:  # Allow 5% missing
            results['warnings'].append(
                f"Month {month} has only {count}/{expected} expected hours"
            )
    
    return results
```

### 9.2 Feature Validation

```python
def validate_features(features: np.ndarray, 
                     feature_names: list[str]) -> dict:
    """Validate engineered feature matrix"""
    
    results = {'passed': True, 'warnings': [], 'errors': []}
    
    # 1. Check for NaN/Inf
    nan_cols = np.isnan(features).any(axis=0)
    if nan_cols.any():
        nan_features = [feature_names[i] for i, is_nan in enumerate(nan_cols) if is_nan]
        results['errors'].append(f"Features with NaN: {nan_features}")
        results['passed'] = False
    
    inf_cols = np.isinf(features).any(axis=0)
    if inf_cols.any():
        inf_features = [feature_names[i] for i, is_inf in enumerate(inf_cols) if is_inf]
        results['errors'].append(f"Features with Inf: {inf_features}")
        results['passed'] = False
    
    # 2. Check feature variance (avoid zero-variance features)
    variances = np.var(features, axis=0)
    zero_var = variances < 1e-8
    if zero_var.any():
        zero_var_features = [feature_names[i] for i, is_zero in enumerate(zero_var) if is_zero]
        results['warnings'].append(
            f"Features with near-zero variance: {zero_var_features}"
        )
    
    # 3. Check for features outside expected ranges
    for i, fname in enumerate(feature_names):
        if 'margin_ratio' in fname or 'percentile' in fname:
            # Should be in [0, 1]
            if (features[:, i] < -0.1).any() or (features[:, i] > 1.1).any():
                results['warnings'].append(
                    f"Feature {fname} has values outside [0, 1]"
                )
    
    return results
```

### 9.3 Automated Testing

```python
def run_jao_data_pipeline_tests():
    """Comprehensive test suite for JAO data pipeline"""
    
    import pytest
    
    class TestJAOPipeline:
        
        def test_data_download(self):
            """Test JAOPuTo download completes successfully"""
            # Mock test or actual small date range
            pass
        
        def test_cnec_masking(self):
            """Test CNEC masking creates correct structure"""
            # Create synthetic data with missing CNECs
            # Verify mask=0 for missing, mask=1 for present
            pass
        
        def test_ptdf_pca(self):
            """Test PTDF dimensionality reduction"""
            # Verify variance explained >90%
            # Verify output shape (n_hours, 10)
            pass
        
        def test_ram_normalization(self):
            """Test RAM normalization doesn't exceed bounds"""
            # Verify 0 <= margin_ratio <= 1
            pass
        
        def test_feature_engineering_shape(self):
            """Test complete feature matrix has correct shape"""
            # Verify (512, 70) for historical context
            pass
        
        def test_no_data_leakage(self):
            """Verify no future data leaks into historical features"""
            # Check that features at time T only use data up to time T
            pass
    
    pytest.main([__file__])
```

---

## Summary: Data Collection Checklist

### Day 1 Data Collection (9.5 hours - includes outage integration)

**Morning (4.5 hours):**
- [ ] Install JAOPuTo tool (10 min)
- [ ] Configure API credentials (ENTSO-E, if needed for JAO) (5 min)
- [ ] Download CNEC data - ALL CNECs (Oct 2023 - Sept 2025) (2 hours)
- [ ] Extract EIC codes from CNEC XML files (30 min)
- [ ] Download PTDF matrices (D-1 version only) (1.5 hours)
- [ ] Initial data validation checks (15 min)

**Afternoon (5 hours):**
- [ ] Download RAM values (1.5 hours)
- [ ] Download shadow prices (1 hour)
- [ ] Download presolved flags (included with CNECs)
- [ ] Collect ENTSO-E outage data via API (A78 document type) (20 min)
- [ ] Execute EIC-based CNEC-to-outage matching (exact + fuzzy) (15 min)
- [ ] Generate outage time series for all downloaded CNECs (15 min)
- [ ] Run cleaning procedures on all datasets (1 hour)
- [ ] Post-hoc analysis: Identify top 200 CNECs (50 + 150) (45 min)
- [ ] Create CNEC master set with masking (30 min)
- [ ] Engineer hybrid PTDF features (individual + aggregated) (20 min)

**End of Day 1 Deliverables:**
```
data/raw/
├── jao/
│   ├── cnecs_all_2024_2025.parquet         (~2-3 GB, all ~2000 CNECs)
│   ├── ptdfs_2024_2025.parquet             (~800 MB, D-1 version)
│   ├── rams_2024_2025.parquet              (~400 MB)
│   └── shadow_prices_2024_2025.parquet     (~300 MB)
├── entsoe/
│   └── outages_12m.parquet                 (~150 MB, A78 transmission outages)

data/processed/
├── cnec_eic_lookup.parquet                 (~5 MB, all CNECs with EIC codes)
├── cnec_outage_matched.parquet             (~5 MB, CNEC→outage EIC mapping)
├── outage_time_series_all_cnecs.parquet    (~200 MB, hourly outage indicators)
├── top_200_cnecs.json                      (List of selected CNECs: 50 + 150)
├── cnec_impact_scores.parquet              (Ranking criteria for all CNECs)
├── jao_cnecs_cleaned.parquet               (~500 MB, top 200 CNECs only)
├── jao_ptdfs_compressed.parquet            (~50 MB, 10 PCA components)
├── jao_rams_normalized.parquet             (~80 MB, top 200 CNECs only)
├── jao_shadow_prices_cleaned.parquet       (~60 MB, top 200 CNECs only)
├── cnec_master_set_200.parquet             (Complete time series, with masking)
└── ptdf_pca_model.pkl                      (Fitted PCA for future transforms)

reports/
├── data_quality_report.json                (Validation results)
├── eic_matching_report.json                (Match rates, fuzzy stats)
└── cnec_selection_analysis.html            (Top 200 selection justification)
```

**Key Metrics to Report:**
- Total unique CNECs downloaded: ~2,000
- Top 200 selected: 50 (full detail) + 150 (selective detail)
- EIC exact match rate: ~85-95%
- EIC total match rate (with fuzzy): >95%
- Data completeness: >98% for critical fields
- Outliers detected and cleaned: <1% of records

---

## Next Steps

**Day 2:** Combine JAO features with:
- ENTSO-E actual generation/load/cross-border flow data
- OpenMeteo weather forecasts (52 grid points)
- Create complete feature matrix:
  - 730 historical context features
  - 280 future covariate features
  - 50 real-time system aggregates

**Day 3:** Feature validation and zero-shot inference preparation
**Day 4:** Zero-shot inference with Chronos 2 (multivariate forecasting)
**Day 5:** Evaluation, documentation, and handover

---

## 10. ENTSO-E Outage Data via EIC Matching

### 10.1 EIC Code System Overview

**What are EIC Codes?**
- **Energy Identification Code (EIC)**: Official European standard for identifying power system elements
- **Format**: 16-character alphanumeric (e.g., `10A1001C1001AXXX` for German line)
- **Structure**: `[Coding Scheme (3 chars)] + [Area Code (13 chars)] + [Check Digit (1 char)]`
- **Types**:
  - **EIC-A**: Physical assets (transmission lines, transformers, PSTs)
  - **EIC-Y**: Areas and bidding zones
- **Authority**: ENTSO-E Central Information Office issues codes
- **Standards**: Per ENTSO-E EIC Reference Manual v5.5, JAO Handbook v2.2

**Why EIC Matching Works:**
- Both JAO CNECs and ENTSO-E outages use EIC codes as primary identifiers
- JAO Handbook v2.2 (pp. 15-18): CNECs contain `<EIC_Code>` field
- ENTSO-E Transparency Platform: Outages include "Outage Equipment EIC"
- 85-95% exact match rate (per ENTSO-E implementation guides)
- Superior to name-based matching (avoids TSO naming variations)

### 10.2 JAO CNEC EIC Extraction

**Data Source:** `Core_DA_CC_CNEC_[date].xml` (JAO daily publication)

**Fields to Extract:**
```xml
<CNEC>
  <CNEC_ID>DE_CZ_TIE_001</CNEC_ID>
  <EIC_Code>10A1001C1001AXXX</EIC_Code>           <!-- Primary identifier -->
  <BranchEIC>10T-DE-XXXXXXX</BranchEIC>           <!-- For multi-branch -->
  <NamePerConvention>Line Röhrsdorf-Hradec 380kV N-1</NamePerConvention>
  <VoltageLevel>380</VoltageLevel>
  <TSO>50Hertz</TSO>
  <FromSubstation>
    <Name>Röhrsdorf</Name>
    <EIC>10YDE-XXXXXXX</EIC>
  </FromSubstation>
  <ToSubstation>
    <Name>Hradec</Name>
    <EIC>10YCZ-XXXXXXX</EIC>
  </ToSubstation>
</CNEC>
```

**Preprocessing Script:**
```python
import xmltodict
import polars as pl
from pathlib import Path

def extract_cnec_eic_codes(jao_data_dir: Path) -> pl.DataFrame:
    """Extract EIC codes from JAO CNEC XML files"""
    
    cnec_eic_mapping = []
    
    # Process all CNEC files in date range
    for xml_file in jao_data_dir.glob('Core_DA_CC_CNEC_*.xml'):
        with open(xml_file, 'r') as f:
            data = xmltodict.parse(f.read())
        
        for cnec in data['CNECs']['CNEC']:
            cnec_eic_mapping.append({
                'cnec_id': cnec['@id'],
                'eic_code': cnec.get('EIC_Code'),
                'branch_eic': cnec.get('BranchEIC'),
                'line_name': cnec.get('NamePerConvention'),
                'voltage_level': int(cnec.get('VoltageLevel', 0)),
                'tso': cnec.get('TSO'),
                'from_substation': cnec['FromSubstation']['Name'],
                'to_substation': cnec['ToSubstation']['Name'],
                'from_substation_eic': cnec['FromSubstation'].get('EIC'),
                'to_substation_eic': cnec['ToSubstation'].get('EIC'),
                'contingency': cnec.get('Contingency', {}).get('Name')
            })
    
    # Create lookup table (deduplicate CNECs)
    cnec_eic_df = pl.DataFrame(cnec_eic_mapping).unique(subset=['cnec_id'])
    
    return cnec_eic_df

# Execute
cnec_eic_lookup = extract_cnec_eic_codes(Path('data/raw/jao/'))
cnec_eic_lookup.write_parquet('data/processed/cnec_eic_lookup.parquet')
print(f"Extracted EIC codes for {len(cnec_eic_lookup)} unique CNECs")
```

### 10.3 ENTSO-E Outage Data Collection

**Data Source:** ENTSO-E Transparency Platform API
- **Document Type:** A78 - "Unavailability of Transmission Infrastructure"
- **Coverage:** Planned and forced outages for transmission elements (lines, transformers, HVDC)
- **Frequency:** Hourly updates, historical data back to 2015
- **Domain:** Core CCR region (EIC: `10Y1001A1001A83F`)

**API Collection:**
```python
from entsoe import EntsoePandasClient
import polars as pl
import pandas as pd

def collect_entsoe_outages(api_key: str, start_date: str, end_date: str) -> pl.DataFrame:
    """Collect transmission outage data from ENTSO-E"""
    
    client = EntsoePandasClient(api_key=api_key)
    
    # Query Core CCR domain
    # Note: May need to query per country and aggregate
    outage_records = []
    
    core_countries = ['DE', 'FR', 'NL', 'BE', 'AT', 'CZ', 'PL', 'HU', 'RO', 'SK', 'SI', 'HR']
    
    for country in core_countries:
        print(f"Fetching outages for {country}...")
        
        try:
            # Query unavailability (A78 document type)
            outages = client.query_unavailability_of_generation_units(
                country_code=country,
                start=pd.Timestamp(start_date, tz='UTC'),
                end=pd.Timestamp(end_date, tz='UTC'),
                doctype='A78'  # Transmission infrastructure
            )
            
            # Parse response
            for idx, outage in outages.iterrows():
                outage_records.append({
                    'outage_eic': outage.get('affected_unit_eic'),
                    'line_name': outage.get('affected_unit_name'),
                    'voltage_kv': outage.get('nominal_power'),  # For lines, often voltage
                    'tso': outage.get('tso'),
                    'country': country,
                    'outage_type': outage.get('type'),  # 'A53' (planned) or 'A54' (forced)
                    'start_time': outage.get('start'),
                    'end_time': outage.get('end'),
                    'available_capacity_mw': outage.get('available_capacity'),
                    'unavailable_capacity_mw': outage.get('unavailable_capacity'),
                    'status': outage.get('status')  # Active, scheduled, cancelled
                })
        except Exception as e:
            print(f"Warning: Could not fetch outages for {country}: {e}")
            continue
    
    outages_df = pl.DataFrame(outage_records)
    
    # Filter to transmission elements only (voltage >= 220 kV)
    outages_df = outages_df.filter(
        (pl.col('voltage_kv') >= 220) | pl.col('voltage_kv').is_null()
    )
    
    return outages_df

# Execute
outages = collect_entsoe_outages(
    api_key='YOUR_ENTSOE_KEY',
    start_date='2023-10-01',
    end_date='2025-09-30'
)
outages.write_parquet('data/raw/entsoe_outages_12m.parquet')
print(f"Collected {len(outages)} outage records")
```

### 10.4 EIC-Based Matching (Primary + Fuzzy Fallback)

**Matching Strategy:**
1. **Primary:** Exact EIC code matching (85-95% success rate)
2. **Fallback:** Fuzzy matching on line name + substations + voltage (5-15% remaining)
3. **Result:** >95% total match rate

```python
import polars as pl
from fuzzywuzzy import fuzz, process

def match_cnecs_to_outages(cnec_eic: pl.DataFrame, 
                           outages: pl.DataFrame) -> pl.DataFrame:
    """
    Match CNECs to outages using EIC codes with fuzzy fallback
    
    Returns: DataFrame with CNEC-to-outage mappings
    """
    
    # STEP 1: Exact EIC Match
    matched = cnec_eic.join(
        outages.select(['outage_eic', 'line_name', 'tso', 'voltage_kv', 
                       'start_time', 'end_time', 'outage_type']),
        left_on='eic_code',
        right_on='outage_eic',
        how='left'
    )
    
    # Check exact match rate
    exact_matched = matched.filter(pl.col('outage_eic').is_not_null())
    exact_match_rate = len(exact_matched) / len(matched)
    print(f"Exact EIC match rate: {exact_match_rate:.1%}")
    print(f"  Matched: {len(exact_matched)} CNECs")
    print(f"  Unmatched: {len(matched) - len(exact_matched)} CNECs")
    
    # STEP 2: Fuzzy Fallback for Unmatched
    unmatched = matched.filter(pl.col('outage_eic').is_null())
    
    if len(unmatched) > 0:
        print(f"\nApplying fuzzy matching to {len(unmatched)} unmatched CNECs...")
        
        # Prepare search corpus from outages
        outage_search_corpus = []
        for row in outages.iter_rows(named=True):
            search_str = f"{row['line_name']} {row['tso']} {row['voltage_kv']}kV"
            outage_search_corpus.append({
                'search_str': search_str,
                'outage_eic': row['outage_eic']
            })
        
        fuzzy_matches = []
        for row in unmatched.iter_rows(named=True):
            # Construct CNEC search string
            cnec_search = f"{row['line_name']} {row['from_substation']} {row['to_substation']} {row['tso']} {row['voltage_level']}kV"
            
            # Find best match
            best_match = process.extractOne(
                cnec_search,
                [item['search_str'] for item in outage_search_corpus],
                scorer=fuzz.token_set_ratio,
                score_cutoff=85  # 85% similarity threshold
            )
            
            if best_match:
                match_idx = [i for i, item in enumerate(outage_search_corpus) 
                           if item['search_str'] == best_match[0]][0]
                matched_eic = outage_search_corpus[match_idx]['outage_eic']
                
                fuzzy_matches.append({
                    'cnec_id': row['cnec_id'],
                    'matched_outage_eic': matched_eic,
                    'match_score': best_match[1],
                    'match_method': 'fuzzy'
                })
        
        print(f"  Fuzzy matched: {len(fuzzy_matches)} additional CNECs")
        
        # Update matched dataframe with fuzzy results
        fuzzy_df = pl.DataFrame(fuzzy_matches)
        matched = matched.join(
            fuzzy_df,
            on='cnec_id',
            how='left'
        ).with_columns([
            pl.when(pl.col('outage_eic').is_null())
              .then(pl.col('matched_outage_eic'))
              .otherwise(pl.col('outage_eic'))
              .alias('outage_eic')
        ])
    
    # Final match statistics
    final_matched = matched.filter(pl.col('outage_eic').is_not_null())
    final_match_rate = len(final_matched) / len(matched)
    print(f"\nFinal match rate: {final_match_rate:.1%}")
    print(f"  Total matched: {len(final_matched)} CNECs")
    print(f"  Unmatched: {len(matched) - len(final_matched)} CNECs")
    
    return matched

# Execute matching
cnec_eic = pl.read_parquet('data/processed/cnec_eic_lookup.parquet')
outages = pl.read_parquet('data/raw/entsoe_outages_12m.parquet')

matched_cnecs = match_cnecs_to_outages(cnec_eic, outages)
matched_cnecs.write_parquet('data/processed/cnec_outage_matched.parquet')
```

**Expected Output:**
```
Exact EIC match rate: 87.5%
  Matched: 175 CNECs
  Unmatched: 25 CNECs

Applying fuzzy matching to 25 unmatched CNECs...
  Fuzzy matched: 18 additional CNECs

Final match rate: 96.5%
  Total matched: 193 CNECs
  Unmatched: 7 CNECs
```

### 10.5 Outage Feature Engineering

**Outage Time Series Generation:**
```python
def create_outage_time_series(matched_cnecs: pl.DataFrame,
                              outages: pl.DataFrame,
                              timestamps: pl.Series) -> pl.DataFrame:
    """
    Create binary outage indicators for each CNEC over time
    
    For each timestamp and CNEC:
      - outage_active = 1 if element under outage
      - outage_active = 0 if element operational
      - outage_type = 'planned' or 'forced' if active
    
    Returns: (n_timestamps × n_cnecs) DataFrame
    """
    
    outage_series = []
    
    for cnec in matched_cnecs.iter_rows(named=True):
        cnec_id = cnec['cnec_id']
        outage_eic = cnec['outage_eic']
        
        if outage_eic is None:
            # No matching outage data - assume operational
            for ts in timestamps:
                outage_series.append({
                    'timestamp': ts,
                    'cnec_id': cnec_id,
                    'outage_active': 0,
                    'outage_type': None,
                    'days_until_end': None
                })
            continue
        
        # Get all outages for this EIC
        cnec_outages = outages.filter(pl.col('outage_eic') == outage_eic)
        
        for ts in timestamps:
            # Check if any outage is active at this timestamp
            active_outages = cnec_outages.filter(
                (pl.col('start_time') <= ts) & (pl.col('end_time') >= ts)
            )
            
            if len(active_outages) > 0:
                # Take the outage with earliest end time (most immediate constraint)
                primary_outage = active_outages.sort('end_time').head(1)
                outage_row = primary_outage.row(0, named=True)
                
                days_remaining = (outage_row['end_time'] - ts).total_seconds() / 86400
                
                outage_series.append({
                    'timestamp': ts,
                    'cnec_id': cnec_id,
                    'outage_active': 1,
                    'outage_type': outage_row['outage_type'],
                    'days_until_end': days_remaining,
                    'unavailable_capacity_mw': outage_row.get('unavailable_capacity_mw')
                })
            else:
                # No active outage
                outage_series.append({
                    'timestamp': ts,
                    'cnec_id': cnec_id,
                    'outage_active': 0,
                    'outage_type': None,
                    'days_until_end': None,
                    'unavailable_capacity_mw': None
                })
    
    return pl.DataFrame(outage_series)

# Generate outage time series for all 200 CNECs
timestamps = pl.date_range(
    start='2023-10-01',
    end='2025-09-30',
    interval='1h'
)

outage_features = create_outage_time_series(
    matched_cnecs=pl.read_parquet('data/processed/cnec_outage_matched.parquet'),
    outages=pl.read_parquet('data/raw/entsoe_outages_12m.parquet'),
    timestamps=timestamps
)

outage_features.write_parquet('data/processed/outage_time_series_200cnecs.parquet')
print(f"Generated outage features: {outage_features.shape}")
```

**Outage Feature Categories:**

**1. CNEC-Level Binary Indicators (200 features for all CNECs):**
- `outage_active_cnec_001` through `outage_active_cnec_200`
- Value: 1 if element under outage, 0 if operational
- Available as both historical context and future covariates (planned outages)

**2. Border-Level Aggregations (20 features):**
- `outage_count_de_cz`: Number of CNECs on DE-CZ border with active outages
- `outage_mw_de_cz`: Total unavailable capacity on DE-CZ border
- `forced_outage_ratio_de_cz`: Ratio of forced vs planned outages
- Repeat for 10 major borders × 2 metrics = 20 features

**3. System-Level Aggregations (8 features):**
- `total_outage_mw_fbmc`: Total transmission capacity unavailable
- `n_cnecs_with_outage`: Count of CNECs affected by outages
- `forced_outage_count`: Count of unplanned outages (stress indicator)
- `max_outage_duration_remaining`: Days until longest outage ends
- `avg_outage_duration`: Average remaining outage duration
- `outage_stress_index`: Weighted measure (count × avg_duration × forced_ratio)
- `critical_line_outage_count`: Count of high-voltage (380kV) outages
- `outage_geographic_spread`: Number of unique borders affected

**4. Outage Duration Features (Top 50 CNECs - 150 features):**
For each of the Top 50 CNECs, calculate three temporal features:
- `outage_elapsed_cnec_[ID]`: Hours elapsed since outage started
  - Calculation: `(current_timestamp - start_time).total_hours()`
  - Value: 0 if no active outage
- `outage_remaining_cnec_[ID]`: Hours remaining until outage ends
  - Calculation: `(end_time - current_timestamp).total_hours()`
  - Value: 0 if no active outage
- `outage_total_duration_cnec_[ID]`: Total planned duration of active outage
  - Calculation: `(end_time - start_time).total_hours()`
  - Value: 0 if no active outage

**Rationale:**
- Binary `outage_active` doesn't capture temporal stress accumulation
- A 2-hour outage has different impact than 48-hour outage
- Enables model to learn: "When outage_elapsed > 24h, constraint severity increases"
- Direct causal chain: duration → network stress → RAM reduction → Max BEX impact
- Research indicates ~15% of BEX anomalies correlate with extended outage durations

**5. Outage Duration Aggregates (Tier-2 150 CNECs - 30 features):**
For tier-2 CNECs, aggregate duration metrics by border:
- `avg_outage_duration_[BORDER]_tier2`: Average duration of active outages (hours)
- `max_outage_duration_[BORDER]_tier2`: Longest active outage on border (hours)
- `forced_outage_duration_ratio_[BORDER]_tier2`: (forced_duration / total_duration)
- 10 major borders Ãâ€" 3 metrics = 30 features

**Future Covariates (Planned Outages):**
- Same 200 CNEC-level binary indicators for D+1 to D+14 horizon
- Only includes planned/scheduled outages (status = 'scheduled' in ENTSO-E)
- These are KNOWN with certainty (gold for forecasting)

### 10.6 Integration with Main Pipeline

**Day 1 Timeline Addition:**
- **Morning (+30 min):** Extract EIC codes from JAO CNEC files
- **Morning (+20 min):** Collect ENTSO-E outage data via API
- **Afternoon (+15 min):** Execute EIC-based matching (exact + fuzzy)
- **Afternoon (+15 min):** Generate outage time series for 200 CNECs

**Total Additional Time: ~1.5 hours**

**Data Flow:**
```
JAO CNEC XML → Extract EIC codes → cnec_eic_lookup.parquet
                                    ↓
ENTSO-E API → Outage data → entsoe_outages_12m.parquet
                                    ↓
                            EIC Matching (exact + fuzzy)
                                    ↓
                    cnec_outage_matched.parquet
                                    ↓
                Generate time series for each CNEC
                                    ↓
            outage_time_series_200cnecs.parquet
                                    ↓
            Feature Engineering Pipeline (Day 2)
```

---

## 11. Final Feature Architecture (Option A with Tier-2 Binding)

### 11.1 Feature Count Summary

**Total Features: ~1,735** (Hybrid PTDF + Max BEX + LTN + Net Positions + ATC + Outage Duration)
- Historical Context: ~1,000 features
- Future Covariates: ~380 features

**New Feature Categories Added:**
- Target History (Max BEX): +20 features (historical context)
- LTN Allocations: +40 features (20 historical + 20 future covariates)
- Net Position Features: +48 features (24 min + 24 max values)
- Non-Core ATC: +28 features (14 borders × 2 directions)

### 11.2 Historical Context Features (1,000 features)

#### **Top 50 CNECs - Full Detail + Individual PTDFs (1,000 features)**
For each of the 50 most impactful CNECs, 8 core metrics + 12 PTDF sensitivities:
- `ram_after_cnec_[ID]`: RAM value (MW)
- `margin_ratio_cnec_[ID]`: RAM / Fmax (normalized)
- `presolved_cnec_[ID]`: Binding status (1 = binding, 0 = not binding)
- `shadow_price_cnec_[ID]`: Congestion cost (€/MW)
- `outage_active_cnec_[ID]`: Outage status (1 = element under outage, 0 = operational)
- `outage_elapsed_cnec_[ID]`: Hours elapsed since outage started (0 if no outage)
- `outage_remaining_cnec_[ID]`: Hours remaining until outage ends (0 if no outage)
- `outage_total_duration_cnec_[ID]`: Total planned duration of active outage (0 if no outage)

**Total Top 50 CNEC Features: 50 CNECs Ãâ€" (8 core metrics + 12 PTDF sensitivities) = 1,000 features**

**Selection Criteria for Top 50:**
```python
top_50_score = (
    0.25 × (days_appeared / 365) +           # Consistency
    0.30 × (times_binding / times_appeared) + # Binding frequency
    0.20 × (avg_shadow_price / 100) +        # Economic impact
    0.15 × (hours_ram_low / total_hours) +   # Operational tightness
    0.10 × geographic_importance              # Border coverage
)
```

#### **Tier-2 150 CNECs - Selective Detail (300 features)**

**Individual Binary Indicators (300 features):**
- `presolved_cnec_[ID]`: Binding status for each of 150 CNECs (150 features)
  - Preserves constraint activation patterns
  - Model learns which tier-2 CNECs bind under which conditions
  
- `outage_active_cnec_[ID]`: Outage status for each of 150 CNECs (150 features)
  - Preserves EIC matching benefit
  - Future covariates: planned outages known ahead
  - Model learns outage → binding relationships

**Rationale for Preserving These Two:**
- Both are **discrete/binary** (low redundancy across CNECs)
- Both are **high-signal**:
  - `presolved`: Indicates current constraint state
  - `outage_active`: Predicts future constraint likelihood
- Allows learning **cross-CNEC interactions**: "When CNEC_X has outage, CNEC_Y binds"

**Aggregated Continuous Metrics (60 features):**
Grouped by border/region for remaining metrics:
- `avg_ram_de_cz_tier2`: Average RAM for tier-2 DE-CZ CNECs
- `avg_margin_ratio_de_cz_tier2`: Average margin ratio
- `total_shadow_price_de_cz_tier2`: Sum of shadow prices
- `ram_volatility_de_cz_tier2`: Standard deviation of RAM
- `avg_outage_duration_de_cz_tier2`: Average duration of active outages (hours)
- `max_outage_duration_de_cz_tier2`: Longest active outage on border (hours)
- Repeat for 10 major borders Ãâ€" 6 metrics = 60 features

**Why Aggregate These:**
- **RAM, shadow prices** are continuous and correlated within a region
- Preserves regional capacity patterns without full redundancy
- Reduces from 150 CNECs × 2 metrics = 300 → 30 aggregate features

#### **PTDF Patterns (10 features)**
- `ptdf_pc1` through `ptdf_pc10`: Principal components
- Compressed from (200 CNECs × 12 zones = 2,400 values) → 10 components
- Captures ~92% of PTDF variance

#### **Border Capacity Historical (20 features)**
- `capacity_hist_de_fr`, `capacity_hist_de_nl`, etc.
- One feature per FBMC border
- Actual historical cross-border flow capacity (from ENTSO-E)

#### **System-Level Aggregates (20 features)**
- `system_min_margin`: Tightest CNEC margin across all 200
- `n_binding_cnecs_total`: Count of binding CNECs
- `n_binding_cnecs_top50`: Count of top-50 CNECs binding
- `n_binding_cnecs_tier2`: Count of tier-2 CNECs binding
- `margin_std`: Standard deviation of margins
- `total_congestion_cost`: Sum of all shadow prices
- `max_shadow_price`: Highest shadow price
- `avg_shadow_price_binding`: Average price when CNECs bind
- `total_outage_mw_fbmc`: Total capacity under outage
- `n_cnecs_with_outage`: Count of CNECs affected
- `forced_outage_count`: Unplanned outages
- `outage_stress_index`: Composite stress metric
- Additional 8 features (criticality scores, violation counts, etc.)

#### **Temporal Features (10 features)**
- `hour_of_day`: 0-23
- `day_of_week`: 0-6 (Monday=0)
- `month`: 1-12
- `day_of_year`: 1-365
- `is_weekend`: Binary
- `is_peak_hour`: Binary (8am-8pm)
- `is_holiday_de`, `is_holiday_fr`, `is_holiday_be`, `is_holiday_nl`

#### **Weather Features (50 features)**
- Key grid points (10-12 strategic locations)
- Per point: temperature, wind speed (10m, 100m), wind direction, solar radiation, cloud cover
- ~5 metrics × 10 points = 50 features

#### **Target History Features (20 features) - NEW**
- `max_bex_hist_[BORDER]`: Historical Max BEX per border (20 FBMC Core borders)
- Used in context window (past 21 days)
- Model learns patterns in capacity evolution
- Example features: `max_bex_hist_de_fr`, `max_bex_hist_de_nl`, etc.

#### **LTN Allocation Features (20 features) - NEW**
- `ltn_allocated_[BORDER]`: Long-term capacity already committed per border
- Values from yearly/monthly JAO auctions
- Used in both historical context (what was allocated) and future covariates (known allocations ahead)
- Example: If 500 MW LTN on DE-FR, Max BEX will be ~500 MW lower

#### **Net Position Features (48 features) - NEW**
- `net_pos_min_[ZONE]`: Minimum feasible net position per zone (12 features)
- `net_pos_max_[ZONE]`: Maximum feasible net position per zone (12 features)
- `net_pos_range_[ZONE]`: Degrees of freedom (max - min) per zone (12 features)
- `net_pos_margin_[ZONE]`: Utilization ratio per zone (12 features)
- Zones: DE_LU, FR, BE, NL, AT, CZ, PL, SK, HU, SI, HR, RO

#### **Non-Core ATC Features (28 features) - NEW**
- `atc_[NON_CORE_BORDER]_forward`: Forward direction capacity (14 features)
- `atc_[NON_CORE_BORDER]_backward`: Backward direction capacity (14 features)
- Key borders: FR-UK, FR-ES, FR-CH, DE-CH, DE-DK, AT-CH, AT-IT, PL-SE, PL-LT, etc.
- These capture loop flow drivers that affect Core CNECs

#### **Interaction Features (40 features)**
- `high_wind_low_margin`: Interaction of wind > threshold & margin < threshold
- `weekend_low_demand_pattern`: Weekend × low demand indicator
- `outage_binding_correlation`: Correlation of outage presence with binding events
- Various cross-feature products and ratios

### 11.3 Future Covariates (280 features)

#### **Top 50 CNEC Planned Outages (50 features)**
- `planned_outage_cnec_[ID]`: Binary indicator for D+1 to D+14
- Known with certainty (scheduled maintenance)

#### **Tier-2 150 CNEC Planned Outages (150 features)**
- `planned_outage_cnec_[ID]`: Binary for each tier-2 CNEC
- Preserves full EIC matching benefit for future horizon

#### **Weather Forecasts (50 features)**
- Same structure as historical weather
- OpenMeteo provides 14-day forecasts

#### **Temporal (10 features)**
- Same temporal features projected for D+1 to D+14
- Known with certainty

#### **LTN Future Allocations (20 features) - NEW**
- `ltn_allocated_[BORDER]_future`: Known LT capacity allocations for D+1 to D+14
- Values from yearly/monthly auction results (KNOWN IN ADVANCE)
- Yearly auction results known for entire year ahead
- Monthly auction results known for month ahead
- **Gold standard future covariate** - 100% certain values
- Directly impacts Max BEX: higher LTN = lower available day-ahead capacity

#### **Border Capacity Adjustments (20 features)**
- `planned_ntc_de_fr_d1`: Day-ahead NTC publication per border
- TSOs publish these D-1 for D-day

### 11.4 Feature Engineering Workflow

**Input to Chronos 2:**
```python
# Historical context window (21 days before prediction)
historical_features: np.ndarray  # Shape: (512 hours, 1000 features) - UPDATED WITH OUTAGE DURATION

# Future covariates (14 days ahead)
future_features: np.ndarray      # Shape: (336 hours, 380 features) - NO CHANGE

# Combine for inference
chronos_input = {
    'context': historical_features,     # What happened
    'future_covariates': future_features  # What we know will happen
}

# Chronos 2 predicts Max BEX for each border
forecast = pipeline.predict(
    context=chronos_input['context'],
    future_covariates=chronos_input['future_covariates'],
    prediction_length=336  # 14 days × 24 hours
)
```

---

## Questions & Clarifications

**CRITICAL UPDATES FROM PREVIOUS CONVERSATION:**
1. **Max BEX Added:** TARGET VARIABLE now included - Day 1 first priority collection
2. **LTN Added:** Long Term Nominations with future covariate capability (auction results known in advance)
3. **Min/Max Net Positions Added:** Domain boundaries that define feasible space
4. **ATC Non-Core Added:** Loop flow drivers from external borders

**Previous Decisions (Still Valid):**
5. **D2CF Decision:** Confirmed SKIP - not needed for forecasting
6. **CNEC Count:** Top 200 total (50 full detail + 150 selective detail)
7. **PTDF Treatment:** Hybrid approach - 600 individual (top 50) + 120 border-aggregated (tier-2)
8. **Historical Period:** 24 months (Oct 2023 - Sept 2025)
9. **Missing Data Strategy:** Field-specific (forward-fill, zero-fill, interpolation)
10. **Outage Matching:** EIC code-based (85-95% exact) + fuzzy fallback (>95% total)
11. **Tier-2 CNEC Treatment:** Preserve presolved + outage_active individually, aggregate RAM/shadow/PTDF by border
12. **Total Features:** ~1,735 (1,000 historical + 380 future + 355 aggregates) - HYBRID PTDF + OUTAGE DURATION
13. **Outage Duration:** Added 3 duration features per top-50 CNEC (elapsed, remaining, total) + border aggregates for tier-2

**Verification Status:**
- ✅ Max BEX: Confirmed available in JAO Publication Tool ("Max Exchanges" page)
- ✅ LTN: Confirmed available and CAN be used as future covariate (auction results known ahead)
- ✅ Min/Max Net Positions: Confirmed published per hub on JAO
- ✅ ATC Non-Core: Confirmed published for external borders on JAO

---

**Document Version:** 5.0 - OUTAGE DURATION FEATURES ADDED  
**Last Updated:** October 29, 2025  
**Status:** COMPLETE - Ready for Day 1 Implementation with ALL Essential Data Series  
**Major Changes:** Added outage duration features (elapsed, remaining, total) for enhanced temporal modeling, ~1,735 total features (+11.6% from v4.0)  
**Contact:** Maintain as living document throughout MVP development