Power grid islanding detection and anti-islanding protection method for large-scale wind power generation system

Abstract

The invention discloses a power grid islanding detection and anti-islanding protection method for a large-scale wind power generation system. The method includes the following steps that: a node type list and a node connection list are initialized; circuit breaker tripping signals in a power grid are monitored, and the node connection list is updated according to the monitored circuit breaker tripping signals, nodes corresponding to the circuit breaker tripping signals are pushed into a queue; and logical judgment is carried out according to the updated node connection list and the queue, so that whether the nodes corresponding to the circuit breaker tripping signals are islanded can be judged. The method is used for the large-scale wind power generation system and carries out islanding detection and anti-islanding protection at a high-voltage main grid of a power source side. The power grid islanding detection and anti-islanding protection method is advantageous in being fast, accurate, efficient, safe and stable. According to the power grid islanding detection and anti-islanding protection method provided by the technical scheme of the invention, line weight does not require to be considered, and therefore, anti-islanding protection actions can be performed more rapidly.

Description

technical field [0001] The invention relates to the field of anti-islanding protection for large-scale wind power generation, in particular to a grid island detection and anti-islanding protection method for large-scale wind power. Background technique [0002] The island state of a large wind farm (base) refers to the operating state in which some wind turbines in a large wind farm (base) continue to supply power to the loads under them after they are disconnected from the main grid. In large-scale wind power generation systems, effective and timely detection of isolated islands is of great significance to wind turbines and local loads. The principles and situations caused by large-scale wind power access to isolated islands are different from those in the distribution network. Therefore, the harm of large-scale wind power access to isolated islands is also different from the harm of isolated islands in the distribution network. First of all, after the islanding of large-s...

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Problems solved by technology

2) The unique fault characteristics of the wind turbine. The wind turbine converter generally performs current control. The wind turbine is boosted through a step-by-step transformer. The wind turbine also needs to send electric energy to the booster station through a long collector feeder. In this system There is a large reactance, the system impedance is large, and the electromagnetic environment is relatively complex. Under sudden power failure, a large transient overvoltage will be generated

3) The island system is an unstable system, and its damping is small, which will generate a large transient overvoltage

4) If the system is not powered off at the beginning of reclosing, there will be an impulse voltage, and the more serious situation is that non-synchronous reclosing occurs. At this time, a large transient overvoltage will appear

Disadvantages of this method: additional equipment is required, high implementation cost, complex operation, many certifications are required, and low economy

[0028] The paper "Distributed Power Generation Islanding Method Based on Improved Prim Algorithm" proposes a minimum spanning tree algorithm based on the Prim method for the islanding problem of the user-side low-voltage distribution network, which does not involve the high-voltage main network on the power supply side. Anti-islanding detection, and because the line weight needs to be considered, the anti-islanding protection action delay is relatively large

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