Hybrid Wind Farm Power Control for Grid Frequency Stability

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Solution Overview

Problem

Conventional control structures for wind farms either lack coordination, leading to inefficiencies and accuracy issues in responding to grid frequency deviations, or suffer from slow response times due to centralized control systems, which fail to meet stringent grid operator requirements.

Innovation Solution

A hybrid control process where each generating unit calculates its active power variation based on a parameter received from a central control unit, allowing immediate response to frequency deviations while ensuring coordinated action, with parameters updated continuously to account for changes in operating conditions, ensuring fast and accurate power adjustments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If centralized control is used to coordinate power output of all wind turbines, then coordination and efficiency are improved, but response time to frequency deviations increases beyond 100 ms

Engineering Contradiction:
Improvecoordination accuracyVSAvoidresponse time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The control system is segmented into local control units at each wind turbine and a central control unit. Each local control unit can independently adjust power output based on frequency deviations, eliminating the need to wait for centralized commands while maintaining coordinated control through the central unit's oversight capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The control parameters and coordination strategies are pre-configured in the local control units during system initialization. When frequency deviations occur, local units can immediately execute pre-planned control actions without waiting for real-time centralized computation and communication, achieving both speed and coordination.

Inventive Principle:
Principle #10Preliminary action

2Loss of time

If local control is used at each wind turbine, then response time is fast, but coordination among turbines is lost leading to efficiency errors

Engineering Contradiction:
Improveresponse timeVSAvoidcoordination accuracy
Core Design Contradiction:
Loss of timeVSReliability

Solution Approach 1:

The central control unit continuously monitors the actual power output of each wind turbine and compares it with the desired coordinated output. Based on this feedback, the central unit adjusts control parameters and communicates updates to local control units, ensuring that individual fast responses collectively achieve the desired farm-level coordination and efficiency.

Inventive Principle:
Principle #23Feedback

3Reliability

If active power control requirements are imposed on distributed generation plants, then grid stability is improved, but system complexity increases

Engineering Contradiction:
Improvegrid stabilityVSAvoidcontrol system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Each wind turbine's local control unit autonomously monitors grid frequency and independently adjusts its power output in response to frequency deviations. This self-service capability eliminates the need for complex real-time centralized control computations and communications, simplifying the overall system while maintaining grid stability through distributed autonomous control.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP2393179B1System and process for controlling active power in a power generation plant
Publication Date: 2020.08.12 NORDEX ENERGY SPAIN SAU
  • EP2393179B1 patent drawingFigure 1
  • EP2393179B1 patent drawingFigure 2
  • EP2393179B1 patent drawingFigure 3

AI summary

The object of the present invention is a process for controlling the active power injected into the grid by a generating plant for contributing to the stability of the power grid in the event of frequency variations wherein in response to a deviation in grid frequency (7), each generating unit (2) calculates an active power variation parameter generated based on a first parameter (Ci, Ki) stored in said generating unit (2), said first parameter (Ci, Ki) being representative of a respective contribution of said generating unit (2) to a required variation in total active power of the generating plant (1),and where a central control unit (5) of the generating plant (1) connected to each generating unit (2) updates the value of the first parameters (Ci, Ki) when changes are produced therein.