Zero-phase open-circuit protection circuit breaker

Abstract

The invention relates to a zero-phase open-circuit protection circuit breaker, and the circuit breaker comprises a zero-sequence mutual inductor, an electric leakage release and a piezoresistor; the primary side of the zero-sequence mutual inductor is encircled with a phase line main circuit and a zero line main circuit, and the secondary side of the zero-sequence mutual inductor is connected withthe signal input end of the electric leakage release; one end of the piezoresistor is connected with the zero line main circuit, and the other end of the piezoresistor is connected with the ground terminal; the operating voltage of the piezoresistor is 10-15% of the rated power supply voltage, the piezoresistor adopts a zinc oxide piezoresistor with a circular sheet-shaped sintered structure, theratio of the thickness to the diameter of the piezoresistor is not more than 1: 10, and the sintering raw materials of the piezoresistor comprise zinc oxide powder and alumina heat-conducting fibers.Compared with the prior art, the zero-phase open-circuit protection circuit has the advantages of being capable of achieving effective seamless overvoltage protection on all zero-phase open circuits,low in cost, reliable in performance, wide in application range and the like.

Description

technical field [0001] The invention relates to a power protection device, in particular to a zero-phase open circuit breaker. Background technique [0002] The zero-phase open circuit of single-phase users leads to overvoltage damage to electrical appliances, which occurs in every power supply station, and is more common in summer load peaks. Zero-phase open-circuit damage to electrical appliances often causes the power sector to face high compensation, and it is easy to cause adverse effects on the society of power grid enterprises. The transformers of the three-phase four-wire system are directly grounded, and the neutral line is at the same potential as the earth. Under normal circumstances, the zero line is not charged. In the three-phase four-wire system power supply line, due to the neutral line (neutral line), then Regardless of whether the three-phase load is balanced or not, the voltage of each phase of the load is always equal, about 220V, so it is safe and relia...

AI Technical Summary

Problems solved by technology

However, in some cases, dangerous voltages will appear on the neutral line, which will cause serious economic losses to users due to burnout of electrical appliances

[0003] In this regard, some detection equipment for the open circuit of the neutral line came into being. However, most of them can only detect whether the total zero phase of the circuit breaker on the low-voltage side of the distribution transformer is open. , in the tens to hundreds of milliseconds before tripping, the overvoltage cannot be controlled at all, and the damage time of the overvoltage to electrical equipment is very short, which greatly reduces the protection effect, while the general varistor can only maintain a few hundred microseconds Over-voltage protection, also can not maintain over-voltage protection for a period of time

In addition, the overvoltage protection circuit breakers in the prior art rely on a large number of electronic components, have average reliability and service life, and are expensive, so they cannot be used for open circuits of branch neutral lines in a large number of buildings

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