Method for detecting island by intermittent two-sided reactive power disturbance

A technology of power disturbance and island detection, applied in the direction of frequency measuring devices, measuring power, measuring devices, etc., can solve problems such as damage to electrical equipment, failure to switch on, high cost, etc., and achieve high grid-connected power factor and reduced power factor the effect of the influence

Inactive Publication Date: 2011-08-17
ZHEJIANG UNIV
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Problems solved by technology

[0004] (1) After disconnecting from the grid, the distributed generation device may be damaged due to voltage or frequency out of control;
[0005] (2) Local electrical equipment may be damaged because the voltage or frequency in the island exceeds the safe range;
[0006] (3) Posing a certain threat to personal safety;
[0007] (4) When the island is isolated, if the capacity of the local load is...

Method used

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  • Method for detecting island by intermittent two-sided reactive power disturbance
  • Method for detecting island by intermittent two-sided reactive power disturbance
  • Method for detecting island by intermittent two-sided reactive power disturbance

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Embodiment Construction

[0024] The technical solutions of the present invention will be further elaborated below in conjunction with the accompanying drawings and specific embodiments.

[0025] refer to figure 1 , the grid-connected inverter system using the islanding detection method of intermittent bilateral reactive power disturbance includes a single-phase or three-phase grid-connected inverter 1 controlled by pulse width modulation based on high-frequency switching, used for the connection between the inverter and the grid Transformer 2 for electrical isolation between inverters, relay 3 for inverter grid-connected control, local load 4, grid 5 and grid-connected inverter for generating inverter bridge drive signals, drive blocking signals and grid-connected relay control signals Controller 10, common coupling point voltage sampling module 6, phase-locked loop 7, frequency judgment module 8, island protection module 9, reactive power control regulator 11 and intermittent bilateral reactive power...

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Abstract

The invention discloses a method for island detection by adopting intermittent two-sided reactive power disturbance. A frequency of a voltage of a common coupling point is out of allowance range after an island occurs by introducing the intermittent two-sided reactive power disturbance into the output reactive power of a grid-connected inverter, so that the aim of the island detection is fulfilled. By the method, an island phenomenon can be detected immediately and effectively, and grid-connected power factors are less influenced.

Description

technical field [0001] The invention relates to an island detection technology in the application field of a distributed power generation system and a grid-connected inverter, in particular to an island detection method for intermittent bilateral reactive power disturbances. Background technique [0002] In the new energy distributed power generation, the electric energy generated by wind energy, photovoltaic, etc. is integrated into the grid after power electronic conversion. As an interface between new energy sources and the grid, grid-connected inverters can transform electric energy and control power quality. Generally, the grid-connected inverter system includes a single-phase or three-phase grid-connected inverter controlled by pulse width modulation based on high-frequency switches, a transformer used for electrical isolation between the inverter and the grid, and a transformer used for grid-connected inverters Controlled relays, local loads, power grids and grid-con...

Claims

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Application Information

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IPC IPC(8): G01R31/00G01R23/02
Inventor 徐德鸿张俊沈国桥
Owner ZHEJIANG UNIV
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