A Passive Island Detection Method

Abstract

A passive islanding detection method. The method comprises: after grid-connected operation of a power generation system, first determining, in each power grid period, the relationship between period value deviation of a grid connection point voltage and a set value, also determining whether effective total harmonic voltage values in multiple consecutive power grid periods and an average value thereof meet preset conditions, counting corresponding islanding occurrence counting variables in the above-mentioned process, and finally determining whether an islanding state occurs according to a counting result of the islanding occurrence counting variables. The method solves the problem of the impact on the quality of electric energy by using an active disturbance means in conventional islanding detection methods or of a larger dead zone existing despite using a passive means. In conjunction with two parameter characteristics, including a grid connection point voltage period and a harmonic, an islanding state can be rapidly detected without a dead zone, and the quality of electric energy is not affected since a passive means is used.

Description

technical field [0001] The invention belongs to the field of distributed power generation (such as photovoltaic power generation), and specifically relates to an islanding detection method related to inverter grid-connected safety regulations. Background technique [0002] Most of the existing islanding detection methods are active disturbance detection methods, which will affect the output power quality. However, the existing passive detection methods are generally phase change and frequency change detection methods, and these methods have the problem that the dead zone is too large. Contents of the invention [0003] The purpose of the present invention is to provide a passive island detection method that does not affect power quality and reduces dead zones. [0004] In order to achieve the above object, the technical scheme adopted in the present invention is: [0005] A passive island detection method, the method is: after the power generation system is connected to ...

AI Technical Summary

Problems solved by technology

[0002] Most of the existing island detection methods are active disturbance detection methods, which will affect the quality of output power

However, the existing passive detection methods are generally phase change and frequency change detection methods, and these methods have the problem of excessively large dead zones.

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