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How to model power relations in your O&M simulation case

Overview

The Power Relations feature enables sophisticated power capacity modeling for offshore wind farm infrastructure, specifically for substations, inter-array cables, and export cables.

This feature allows you to define power transmission constraints that the simulation engine uses to calculate power production impacts when infrastructure components fail or are under maintenance.

What is Power Relations?

Power Relations is an advanced feature that models the electrical network topology of your wind farm by assigning power capacity ratings (in MW) to transmission infrastructure.

The simulation uses these capacities to:

  • Calculate power production limitations based on cable and substation ratings

  • Model cascading power impacts when infrastructure fails

  • Determine which turbines are affected by specific cable or substation failures

  • Compute realistic Production-Based Availability (PBA) losses

Applicable Infrastructure

Power Relations can be configured for:

  • Substations (OSS/Offshore Substation)

  • Inter-array cables

  • Export cables

How to Set Up Power Relations

Step 1: Access the Feature

Navigate to your case and access the Infrastructure section where you can configure cables and substations.

Step 2: Configure Power Capacity

For Cables (Inter-Array & Export)

  1. Navigate to your Case → Infrastructure section

  2. Select an Inter-array cable or Export cable

  3. Locate the Power Capacity field in the infrastructure settings

  4. Enter the cable's rated power capacity in MW

  5. Save your changes

Example:

Cable: WTG-001 to OSS-A  
Power Capacity: 42.5 MW

For Substations

  1. Navigate to Infrastructure → Substations

  2. Select the substation you want to configure

  3. Enter the Power Capacity in MW

  4. Save the configuration

Important Notes:

  • Power capacity is entered in MW (megawatts)

  • The simulation engine converts this to kW (kilowatts) internally

  • Conversion:

    Power Capacity (kW) = Power Capacity (MW) × 1,000

How Power Relations Affects Calculations

Power Flow Modeling

When Power Relations is configured, the simulation builds a network model based on:

  1. Cable connections – linking turbines to substations or turbines to each other

  2. Substation capacity – limiting total power that can be exported

  3. Cable capacity – constraining power flow through specific paths

Power Production Impact Calculations

During Normal Operation

The simulation ensures that power production never exceeds the capacity of the transmission path.
If total turbine generation exceeds cable or substation capacity, production is curtailed accordingly.

During Failures or Maintenance

When a cable or substation experiences a failure or undergoes maintenance, the simulation calculates:

  1. Direct Impact – Power from turbines directly connected to the failed component is lost

  2. Capacity-Based Impact – If the failed component has a defined power capacity, only that amount of generation is affected

  3. Disconnect Power Impact – For corrective maintenance tasks, enabling PBA loss calculations for other WTGs models cascading disconnect impacts

Integration with Corrective Maintenance

Severity Configuration Fields

  • Impact on Power – % of power lost when the failure occurs

  • Production Curtailment During Work – % of power lost during repair work

  • PBA loss calculations for other WTGs – Enables cascading power loss modeling

Calculation Example:

Cable Power Capacity = 42.42 MW = 42,420 kW  
Impact on Failure = 100%  
Effective Loss = 42,420 kW × 100% = 42,420 kW

Common Configuration Scenarios

Scenario 1: String Configuration

Multiple turbines connected in series through inter-array cables to a substation.

Setup:

Turbine A (10 MW)
   ↓ Inter-Array Cable 1 (10 MW)
Turbine B (10 MW)
   ↓ Inter-Array Cable 2 (20 MW)
Turbine C (10 MW)
   ↓ Inter-Array Cable 3 (30 MW)
Substation (100 MW)

Result:
If Cable 3 fails, all three turbines (30 MW total) lose production capacity.

Scenario 2: Radial Configuration

Turbines connected directly to the substation via individual cables.

Setup:

Turbine A (10 MW) → Cable A (10 MW) ↘
Turbine B (10 MW) → Cable B (10 MW) → Substation (50 MW)
Turbine C (10 MW) → Cable C (10 MW) ↗

Result:
If Cable A fails, only Turbine A (10 MW) loses production.

Scenario 3: Substation Capacity Limitation

Setup:

Total Turbine Capacity: 500 MW  
Substation Capacity: 400 MW  
Export Cable Capacity: 400 MW

Result:
Maximum export is limited to 400 MW regardless of turbine availability.

Output Impact

Affected Simulation Outputs

When Power Relations is configured, the following outputs are enhanced:

  1. Statistics TBA – Reflects capacity-limited production losses

  2. Power Production Logs – Shows curtailment due to transmission constraints

  3. PBA (Production-Based Availability) – Accounts for partial power losses

  4. Key Metrics Dashboard – Displays utilization metrics and bottlenecks

PBA Root Cause Categories

Power Relations-Specific Root Causes

  1. PBA OSS at max capacity

    • Appears when a substation reaches maximum capacity

    • Example: Substation (400 MW) with 450 MW generation → 50 MW curtailed

  2. PBA Cable at max capacity

    • Appears when a cable reaches its rated power limit

    • Example: 42 MW cable with 50 MW flow → 8 MW curtailed

  3. PBA Other asset in string disconnected

    • Appears when “PBA loss calculations for other WTGs” is enabled

    • Models upstream turbine shutdowns due to disconnection events

Common Issues & Troubleshooting

Issue Symptom Solution
Power Capacity Field Not Visible Field missing in forms Verify correct asset type; refresh browser; check access
Incorrect Power Loss Calculations Unexpected losses Ensure MW not kW, check topology & maintenance settings
Missing or Null Power Capacity Simulation ignores field Ensure numeric MW values only
Power Capacity Not Affecting Results No visible impact Confirm simulation rerun and saved configurations
Unexpected “Other Asset in String Disconnected” Losses Excessive cascading loss Review maintenance configuration and topology

Validation & Testing

Pre-Simulation Checklist

✅ All cables and substations have defined power capacity
✅ Values in MW
✅ Topology verified
✅ “PBA loss calculations for other WTGs” only where applicable

Example Test Scenarios

  • Single Cable Failure: Verify expected loss equals cable capacity

  • Substation Bottleneck: Verify capped production and correct root cause

  • Cascading Failures: Validate “Other asset in string disconnected” losses

  • Normal Operation: Confirm curtailment at rated capacities

Best Practices

  1. Accurate Capacity Modeling: Use rated values, include derating factors

  2. Network Topology Verification: Validate all “from–to” connections

  3. Maintenance Configuration: Enable cascading loss only where appropriate

  4. Incremental Setup: Start with export cables → substations → inter-array

  5. Documentation: Keep a record of topology and assumptions

  6. Result Interpretation: Analyze PBA breakdown for constraint-driven losses

  7. Sensitivity Analysis: Test alternative configurations and upgrades

Related Features

  • Corrective Maintenance – Defines severity and impact

  • PBA Calculations – Integrates capacity constraints

  • Infrastructure Configuration Sharing – Replicates settings

  • Scheduled Maintenance – Can also trigger disconnection-based losses

Support & Resources

For Technical Issues:

  • Check browser console and logs

  • Contact Shoreline support

For Modeling Questions:

  • Review topology diagrams and specs

  • Consult Shoreline support for modeling guidance

For PBA Root Cause Analysis:

  • Review exported reports and dashboards

  • Compare P10/P50/P90 scenarios for loss variability

Appendix: Technical Reference

Power Capacity Storage

  • Stored as Double (MW)

  • Field: power_capacity

Unit Conversion

Input: MW  
Storage: MW  
Simulation: kW  
Conversion: PowerCapacityKw = PowerCapacityMw × 1000

Applicable Categories

  • Inter-array cables (ID: INTERARRAYCABLE)

  • Export cables (ID: EXPORT_CABLE)

  • Substations (ID: SUBSTATION)

Root Cause Generation Logic

Infrastructure Root Cause
Substation PBA OSS at max capacity
Cable PBA Cable at max capacity
Other asset (disconnect) PBA Other asset in string disconnected

Output File Locations

  • Statistics Report: PBA Root Causes sheet

  • Aggregated Results: resultAggregateAndStatisticsPBARootCause.json

  • Dashboard: PBA Root Cause chart