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Distributed power supply active islanding detection device and method

A distributed power supply and island detection technology, which is applied in the direction of measuring devices, measuring electricity, and measuring electrical variables, etc., can solve problems affecting power quality, achieve the effects of eliminating detection blind spots, fast and accurate detection, and reducing impact

Active Publication Date: 2015-11-11
STATE GRID CORP OF CHINA +2
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Problems solved by technology

[0003] The purpose of the present invention is to provide a distributed power active islanding detection device and method to eliminate the problems of detection blind spots and affecting power quality in the current islanding detection process

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  • Distributed power supply active islanding detection device and method
  • Distributed power supply active islanding detection device and method
  • Distributed power supply active islanding detection device and method

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Embodiment Construction

[0025] The specific embodiments of the present invention will be further described below in conjunction with the accompanying drawings.

[0026] An embodiment of a distributed power supply active islanding detection device of the present invention

[0027] The island detection device of the present invention is as figure 1 As shown, including grounding transformer, AC power supply, detection unit, voltage measurement branch and current measurement branch, QF 1 Incoming circuit breaker for 380V system; QF 2 is the circuit breaker in the 380V system; Z L1 ,Z L2 ,Z L3 is the load impedance of other branches in the system, Z t1 is the leakage reactance of the low-voltage side of the 10kV distribution transformer, both of which are at 20Hz, where Z t1 much smaller than other branch impedances. The primary side of the grounding transformer is used to connect to the neutral point of the high-voltage side winding of the isolation transformer of the inverter in the power grid, a...

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Abstract

The invention relates to a distributed power supply active islanding detection device and method, which belongs to the technical field of intelligent power grids. According to the invention, a neutral point of an isolation transformer high voltage side winding of an inverter in a power grid system is connected in series with a grounding transformer; the secondary side of the grounding transformer is connected with a low-frequency alternating current power supply; the alternating current power supply injects a certain amount of low-frequency voltage and low-frequency current into the neutral point in the power grid system through the grounding transformer; the voltage and the current of a measuring circuit composed of the grounding transformer and the alternating current power supply is measured in real time; and according to variation features of voltage and current measurement values before and after an islanding effect, an absolute value amplitude comparison principle is used to carry out islanding detection. According to islanding detection provided by the invention, the alternating current power supply is injected into the neutral point of the isolation transformer high voltage side winding of the inverter in the power grid; detection blind spots are eliminated; the impact of power quality on the power grid is reduced; and islanding detection can be quickly and accurately carried out.

Description

technical field [0001] The invention relates to a distributed power supply active island detection device and method, belonging to the technical field of smart grids. Background technique [0002] Islanding detection is an important function that distributed generation systems and microgrids must have. When the power supply of the grid is repaired due to failure or power outage, the distributed grid-connected power generation system or micro-grid at each user end must detect the power-off state in time and cut itself off from the grid. (i.e. island operation) mode to improve power system security and power supply reliability. The islanding detection method is divided into a passive detection method and an active islanding detection method. The passive detection method is to detect the phase, frequency and harmonic changes of the common point voltage. The method is simple but has detection blind spots. Active detection methods can make up for the deficiencies of passive det...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/00
Inventor 李瑞生郭宝甫田盈王伟翟登辉
Owner STATE GRID CORP OF CHINA
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