Wire-break self diagnosis method and device for current transformer secondary coils

Abstract

The invention relates to a wire-break self diagnosis method and a device for current transformer secondary coils of breakers or other low-voltage electrical appliances. The device comprises a current transformer secondary coil, an electronic tripper, a loaded current device and a detecting device, wherein the electronic tripper comprises a power supply device, a control unit and an actuating device. The method comprises the following steps of: respectively collecting secondary current signal instantaneous values in all secondary coils of a current transformer by the electronic tripper, and working out effective period values of the secondary current instantaneous values; judging whether all the effective period values are zero or not; if so, loading loaded current onto the secondary coils; and after the current is loaded, judging that the secondary coils have wire break by the electronic tripper if the state of a detecting signal output by a detecting device has no change, wherein thepower supply of the loaded current is provided by the power supply device, and the control unit is used for controlling the loaded current device to execute the on / off of the loaded current.

Description

technical field [0001] The invention relates to a method and a device for detecting a disconnection of a secondary coil of a current transformer, in particular to a method and a device for detecting a disconnection of a secondary coil of a current transformer of a circuit breaker, especially to a secondary coil of a current transformer of an intelligent circuit breaker. A coil disconnection self-diagnosis method and device. Background technique [0002] As we all know, current transformers are commonly used components in circuit breakers. Induction current is used as a standardized current for devices such as measuring instruments or relays. With the advent of intelligent circuit breakers, the current transformer and the electronic trip unit (ETU) together constitute an indispensable core component. The smart chip of the electronic trip unit passes the small current collected from the secondary winding of the current transformer. Signal, real-time monitoring of the large c...

AI Technical Summary

Problems solved by technology

At present, most of the circuit breakers (including intelligent circuit breakers) on the market do not have the disconnection detection function of the secondary coil of the current transformer, and some of them with the disconnection self-detection function cannot achieve real-time detection, or the structure is complex , production difficulty and high cost

For example, the invention patent with application number 200610171873.4 discloses an electronic tripping device and a circuit breaker including the tripping device and its control method. It adopts a double-core transformer design scheme, that is, an iron-core transformer for power supply and the air-core transformer used for measurement are independent of each other, and the patent only involves the disconnection detection of the secondary coil of the air-core transformer, but does not have the function of detecting the disconnection of the core current transformer, and the method and structure Complex and expensive to manufacture

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