Wind Plant Reactive Power Control Mode Switching

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Solution Overview

Problem

Wind power plants face challenges in rapidly adjusting reactive power to maintain grid voltage stability, as existing control systems often have slow response times and inefficient switching between master and slave control modes, leading to potential oscillations or inadequate reactive power production during low voltage events.

Innovation Solution

A method that dynamically switches between two control modes for reactive power management in wind power plants, where the STATCOM controller acts as a master during fast voltage control needs and the power plant controller takes over in steady-state conditions, using closed-loop and feedforward control schemes to optimize reactive power production and voltage control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the power plant controller controls reactive power production in closed loop mode, then voltage control stability is improved, but response time deteriorates

Engineering Contradiction:

Improvevoltage control stabilityVSAvoidresponse time

Core Design Contradiction:

Stability of the object's compositionVSLoss of time

Solution Approach 1:

The system dynamically switches between two control modes: closed-loop control for stability during normal operation and open-loop control for fast response during voltage disturbances. The controller can transition from closed-loop to open-loop mode when rapid reactive power adjustment is needed, leveraging the STATCOM's fast response capability while maintaining stability during steady-state operation.

Inventive Principle:

Principle #15Dynamics

2Speed

If the STATCOM controller acts as master in fast voltage control, then response speed is improved, but control complexity increases

Engineering Contradiction:

Improveresponse speedVSAvoidcontrol complexity

Core Design Contradiction:

SpeedVSDevice complexity

Solution Approach 1:

The control system is segmented into two distinct modes with clear functional divisions. In open-loop mode, the STATCOM controller acts as master for fast voltage control. In closed-loop mode, the power plant controller acts as master for stable steady-state operation. This segmentation allows each controller to excel in its designated mode without the complexity of continuous interaction.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system changes the control parameter structure by switching between master-slave configurations. When fast response is needed, the STATCOM becomes the master controller with the power plant controller as slave. During steady-state, the roles reverse. This parameter change in control architecture enables fast response when needed while simplifying control during normal operation.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If switching between control modes is implemented, then adaptability to different operating conditions is improved, but switching reliability deteriorates due to potential oscillations

Engineering Contradiction:

Improveadaptability to different operating conditionsVSAvoidswitching reliability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The system prepares for mode switching by continuously monitoring voltage conditions and pre-configuring the appropriate control mode. When voltage disturbances are detected, the system is already prepared to switch to open-loop mode for fast response. This preliminary preparation ensures smooth transitions without oscillations or reliability issues.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses feedback from voltage measurements to determine when to switch between control modes. During steady-state operation with stable voltage, closed-loop control is maintained. When voltage disturbances exceed threshold values, the feedback triggers a switch to open-loop mode. This feedback-based switching ensures reliable transitions adapted to actual grid conditions without causing oscillations.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS10411480B2Reconfiguration of the reactive power loop of a wind power plant

Publication Date: 2019.09.10 VESTAS WIND SYSTEMS AS

AI summary

The present invention relates a method of controlling a wind power plant connected to an electrical grid, the wind power plant comprises a power plant controller (350), a plurality of wind turbine generators (1) and a STATCOM (230), with a STATCOM controller, comprises: controlling the plurality of wind turbine generators in a first control mode, with the power plant controller controlling a reactive power production from each of the plurality of wind turbine generators according to a closed loop control scheme, and controlling in a first control mode with a closed loop control scheme a reactive power production from the STATCOM according to a first setpoint dispatched from the power plant controller, and controlling the reactive power production from the STATCOM in a second control mode from the STATCOM controller according to an electrical measurement in the grid, and controlling the plurality of wind turbine generators in a second control mode, with the power plant controller controlling a reactive power production from the plurality of wind turbine generators, according to a feedforward control or a close loop control, based on a second setpoint from the STATCOM controller, and switching between the first control mode and the second control mode when receiving at least one trigger signal. The invention also relates to a wind power plant according to the method.