Wind Farm Reactive Power Sharing for Grid Fault Support
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Solution Overview
Problem
Conventional wind turbines with doubly-fed induction generator (DFIG) systems face challenges in managing reactive power during both stable and fault states, particularly during grid faults where the burden on Fault Ride Through (FRT) capability increases, necessitating improved reactive power compensation strategies.
Innovation Solution
A system and method that dynamically adjust the reactive power supply between the generator and a reactive power compensation device, such as a modular VAR Box, to prioritize generator output during faults and maximize real power capacity, while utilizing the compensation device's full capacity during stable states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the generator supplies reactive power during grid faults to support grid voltage, then grid stability is improved, but the burden on FRT capability increases and real power capacity is reduced
Solution Approach 1:
The reactive power supply function is segmented between two sources: the generator and the reactive power compensation device. During stable states, the compensation device handles reactive power demands to free up the generator's real power capacity. During grid faults, the generator prioritizes real power supply while the compensation device provides reactive power support, thus resolving the contradiction between maintaining grid stability and preserving real power capacity.
Solution Approach 2:
The reactive power compensation device acts as an intermediary that handles reactive power compensation tasks during stable operation, allowing the generator to maximize real power output. During fault conditions, the roles are dynamically adjusted with the compensation device providing reactive power support to maintain grid stability while the generator focuses on real power supply, thus mediating the conflict between these two requirements.
2Power
If the reactive power compensation device is used during stable states, then real power capacity of the generator is maximized, but the generator's direct contribution to reactive power demand is reduced
Solution Approach 1:
The system dynamically adjusts the division of reactive power supply between the generator and compensation device based on operating conditions. During stable states, the compensation device supplies reactive power to maximize generator real power capacity. During grid faults, the system dynamically switches roles so the generator provides real power while the compensation device provides reactive power support, ensuring both objectives are met under different conditions.
3Reliability
If the generator supplies all reactive power during faults, then reactive power demand is met, but the overall system reliability and real power output are compromised
Solution Approach 1:
The reactive power supply task is segmented between the generator and compensation device during fault conditions. The compensation device handles the reactive power demand fulfillment while the generator focuses on maintaining real power output, thus resolving the contradiction between meeting reactive power demands and maintaining productivity.
Data Source
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AI summary
A method and associated system for operating a power generation to supply real and reactive power to a grid includes determining a total reactive power demand made on the system during a first, stable grid state. A first reactive power portion of the reactive power demand is supplied by a generator, and a second reactive power portion is supplied by a reactive power compensation device, wherein the second reactive power portion may be greater than the first reactive power portion. Upon detection of a grid fault, the first reactive power portion is increased and the second reactive power portion is decreased.