A Method and Device for Islanding Detection Based on Frequency Feedback Disturbance

Abstract

The invention relates to an island detection method and device based on frequency feedback disturbance, comprising: a preliminary judgment step: detecting grid parameters, and preliminary judging whether to enter the island state; a disturbance step: if entering the island state, the frequency output by the phase-locked loop and the power grid The frequency difference of the frequency is adjusted by the PI controller, which is output to the reactive current control link as the reactive current input reference value iq*+; re-judgment step: check the grid parameters again to judge whether the islanding effect really occurs. The invention combines passive islanding detection with active islanding detection, can reduce the detection blind spot of the inverter, and can detect the occurrence of the islanding phenomenon accurately and quickly; The introduction of harmonics to the grid reduces the impact of the islanding detection algorithm on the total harmonic content of the inverter output current.

Description

technical field [0001] The invention relates to an island detection method and device based on frequency feedback disturbance. Background technique [0002] With the increasing pressure on the global resource environment, energy conservation and emission reduction and resource conservation have become the trend of world economic development. Focusing on the development of green economy and strengthening energy conservation and emission reduction, we will accelerate the goal of building a resource-saving and environment-friendly society" Above. As a widely used energy source, electric energy has penetrated into all aspects of industrial production, society and people's life. At present, the power generation system composed of new energy is represented by wind power and solar grid-connected power generation; With the grid-connected power generation system, the distributed power supply will continue to supply power to the distribution network disconnected from the grid. This ph...

AI Technical Summary

Problems solved by technology

[0004] The passive detection method detects the abnormal phenomenon of the voltage at the common point between the inverter and the grid (such as over / under voltage, over / under frequency), which is easy to miss

Active detection, such as disturbance detection, can overcome detection blind spots by artificially increasing disturbances, but artificial disturbances will increase system harmonics and affect power quality

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