Composite protection low-voltage circuit breaker

Abstract

The invention discloses a composite protection low-voltage circuit breaker, which comprises a release, a zero-sequence induction coil and a composite protection circuit, and is characterized in that the composite protection circuit is connected with the output end of a phase line and the input end of a zero phase of the low-voltage circuit breaker. According to the composite protection circuit, the overvoltage protection function can be achieved only through one high-voltage trigger diode and one resistor, the high-voltage trigger diode serves as a mature passive device with extremely high reliability, and compared with an overvoltage protection device designed through a large number of active detection circuits, the reliability is greatly improved. According to the invention, islanding protection is realized with extremely low cost, and the problem of mis-tripping of the residual-current circuit breaker is solved.

Description

technical field [0001] The invention relates to the field of power protection equipment, in particular to a composite protection low-voltage circuit breaker. Background technique [0002] With the development of power electronics technology, more and more small micro-grids with distributed power sources are put into use. As the basic component of low-voltage distribution network protection, how to adapt to the micro-grid system with distributed power sources is an urgent problem to be solved. The problem. The microgrid system contains a large number of power electronic converters. Due to the special requirements of the converter equipment and the sensitivity to the disturbance of the power supply system, there are special requirements for fault protection. [0003] The ability of power electronic devices to withstand overvoltage stress is poor, and if only relying on the protection of the converter itself, sometimes there will be significant limitations. Some single-phase ...

AI Technical Summary

Problems solved by technology

However, for low-voltage and small-capacity micro-grid systems, such as household photovoltaic systems, etc., due to the relatively simple island protection detection of the inverter itself, problems such as slow shutdown after external power grid failures often occur, and because the shutdown only depends on the converter shutdown , the mechanical disconnection point isolation of the switchgear cannot be realized, so there are still certain hidden dangers

[0005] At the same time, due to the large number of anti-interference grounding capacitors used in power electronic equipment, the capacitive current accumulated by these capacitors will easily cause the leakage circuit breaker to trip by mistake.

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