High-sensitivity earth wire voltage protection device

Abstract

A high-sensitivity ground wire voltage protection device comprises three poles of phase line L, neutral line N and earth wire E which are all provided with a switch, a zero-sequence current transformer passing through the phase line L and the neutral line N, a testing circuit, a first amplifying circuit, a tripper, a rectifier circuit, a power supply voltage reducer and a thyristor, as well as a transformer and a second amplifying circuit, wherein one end of the primary coil of the transformer is connected with the earth wire, while the other end of the same is connected with the neutral line N after being connected in series with a large-resistance current-limiting step-down circuit; the primary coil of the transformer is connected with the input end of the second amplifying circuit; the working power supply of the second amplifying circuit and that of the first amplifying circuit both are connected with the power supply voltage reducer; the output end of the second amplifier circuit is connected in series with a reverse voltage isolating circuit and then is connected with the trigger electrode of the thyristor; and the output end of the first amplifier circuit is also connected in series with a reverse voltage isolating circuit and then is connected with the trigger electrode of the thyristor. The high-sensitivity ground wire voltage protection device is capable of guaranteeing that the live trip voltage of the earth wire is not greater than the safe voltage and preventing malfunction and false alarm.

Description

technical field [0001] The invention relates to a highly sensitive ground wire live voltage protection device. Background technique [0002] The existing live protection device with ground wire, such as the all-round leakage protection plug, generally means that the protection device (plug) can be disconnected when there is leakage in the phase and neutral wire, and it can also be disconnected when the ground wire is charged. Including the phase, zero, and ground three poles connected by the moving contact elastic sheet and the static contact, passing through the zero-sequence current transformer between the phase and neutral wires, the test circuit, the amplifier circuit, the rectifier, the thyristor, and the release device 1. The zero-sequence current transformer that passes through the ground wire. In addition to detecting whether there is leakage current between the load phase and the neutral wire, it also detects whether there is leakage current through the ground wire....

AI Technical Summary

Problems solved by technology

[0004] However, the above-mentioned all-round leakage protection plug also has the following disadvantages: 1. When the zero-sequence transformer on the ground is used to detect the current, the current on the user's ground is very complicated, and it is easy to generate current between the ground and cause false tripping

[0005] 2. When the neon lamp cooperates with the photosensitive element to detect the ground voltage, the starting voltage of the neon lamp is above 70V, so it cannot be tripped within the safe voltage for protection

Images