Electronic less/over-voltage protective device for low-voltage circuit breaker and control method thereof

Abstract

The present invention relates to a low-voltage circuit breaker electronic undervoltage and overvoltage protection device and a control method. The device consists of voltage transformers of A, B, C, N phases on the incoming end of an acquisition circuit breaker, a precise operational amplifier, an electronic strobe switch, a single-chip microcomputer, a relay and a circuit breaker executive mechanism. Voltage transformers of A, B, C phases input a voltage signal to the input ports of the precise operational amplifier; the precise operational amplifier inputs the signal after the treatment to the I / O port of the single-chip microcomputer through the electronic strobe switch; the single-chip microcomputer measures the signal of each phase and compares with the qualified range value in a logic program; if one phase signal is not qualified, the single-chip microcomputer outputs the signal to the relay through the I / O port; the NC node of the relay is connected to a switch opening executive mechanism of the relay. The intelligent device with the microprocessor as the core, plus the control flow procedures of the microprocessor, can improve the sampling precision and ensure the action reliability of low-voltage circuit breaker.

Description

technical field [0001] The invention belongs to a circuit breaker, in particular to an electronic undervoltage and overvoltage protection device and a control method for a low-voltage circuit breaker. Background technique [0002] my country's low-voltage electrical appliances have experienced many years of development history, and have made a qualitative leap from functional categories to quality characteristics. Short-circuit and overload protection are the traditional protection forms of low-voltage electrical appliances. Voltage protection is not very important. Some lines only protect against undervoltage, but undervoltage and overvoltage faults also cannot make the load work reliably. The traditional undervoltage release is realized by the electromagnetic system, and the moving iron core is controlled by the gain and loss of the electromagnetic coil, thereby controlling the action of the circuit breaker. This structure has two disadvantages. One is that it is installe...

AI Technical Summary

Problems solved by technology

This structure has two disadvantages. One is that it is installed on the circuit breaker mechanism and used in conjunction with the mechanism. Sometimes the moving iron core of the undervoltage release will be stuck with the mechanism; the other is that its power cord has only two wires. It can detect the zero wire and the live wire or the live wire and the live wire; this has certain limitations, and in practice, voltage faults may occur in each phase of the three-phase power supply line

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