Wind Plant Reactive Power Control via Voltage Measurement

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Solution Overview

Problem

Existing power plant control systems face challenges in regulating reactive power exchange based solely on active power measurements, leading to potential disconnection of generators, power plants, or grid instability.

Innovation Solution

A method for controlling renewable energy power plants that involves measuring voltage levels at the point of interconnection, calculating reactive power exchange limits based on these measurements, and adjusting operations to ensure these limits are not exceeded, thereby maintaining safe operation of both the power transmission network and generators.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If reactive power exchange is limited based only on active power measurements, then power delivery demands can be implemented, but generator disconnection or grid instability may occur

Engineering Contradiction:

Improvepower deliveryVSAvoidgrid stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent changes the basis for reactive power limits from active power measurements to voltage level measurements. By measuring voltage at the point of interconnection and calculating reactive power limits based on voltage thresholds (e.g., Qmax at low voltage, Qmin at high voltage), the system adapts to actual grid conditions, preventing generator disconnection and maintaining stability while still meeting power delivery requirements

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If reactive power limits are set strictly according to P-Q charts, then grid code requirements are met, but disconnection of generators or power plant may occur during voltage fluctuations

Engineering Contradiction:

Improvegrid code complianceVSAvoidcontinuous operation

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent introduces dynamic reactive power limits that adjust with voltage fluctuations. Instead of fixed P-Q chart limits, the system calculates time-varying limits based on measured voltage levels, allowing the power plant to maintain continuous operation during voltage changes while still complying with grid code requirements at all times

Inventive Principle:

Principle #15Dynamics

3Reliability

If voltage level measurement and dynamic limit calculation are implemented, then grid stability is maintained, but control system complexity increases

Engineering Contradiction:

Improvegrid stabilityVSAvoidcontrol system

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical protection systems with an electronic control system that measures voltage levels and calculates reactive power limits using programmed logic. This substitution allows dynamic adaptation to voltage changes while maintaining simpler overall system architecture compared to multiple protective relays and switches

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS10778010B2Relating to reactive power control in wind power plants

Publication Date: 2020.09.15 VESTAS WIND SYSTEMS AS

AI summary

A method for controlling a renewable energy power plant comprising a plurality of wind turbine generators, the method comprising: measuring a voltage level associated with a point of interconnection between a power transmission network and the power plant; calculating a reactive power exchange limit based upon the measured voltage level; and controlling the power plant so that the calculated reactive power exchange limit is not exceeded.