Three-phase-circuit phase selection switch system and method for preventing failure and short circuit of relay

Abstract

The invention relates to a phase-selection-circuit phase selection switch system and method for preventing failure and a short circuit of a relay. In the phase-selection-circuit phase selection switchsystem for preventing the failure and the short circuit of the relay, every phase comprises a combination switch composed of a semiconductor switch and a relay, a relay breaking feedback circuit anda semiconductor switch trigger circuit, wherein the combination switch is composed of the semiconductor switch and the relay, and the relay breaking feedback circuit and the semiconductor switch trigger circuit are connected in series to be connected with a combination switch A in parallel. Compared with the prior art, the phase-selection-circuit phase selection switch system and method have the advantages that the phase conversion process is safe and reliable, and occurrence of a short-circuit fault caused when a relay is abnormal and cannot be switched off can be avoided; a current sensor isomitted, relay sections are detected through electron devices, and the product cost can be reduced in aspects of the product material cost and product processing.

Description

Technical field: [0001] The invention relates to the treatment of three-phase unbalance in a low-voltage power grid, and further relates to a three-phase circuit phase selection switch system and method for preventing relay failure and short circuit. Background technique: [0002] The three-phase unbalance of the low-voltage power grid has always been one of the main problems that plague the power supply unit. At present, in the three-phase unbalance control scheme of the low-voltage distribution station area, the scheme of using a phase selection switch is an ideal solution. This solution can essentially solve the problem of unbalanced three-phase load on the line. Not only the product itself has low operating loss, stable operation, and long life, it can also reduce the overall line loss and generate economic benefits. The phase-selection unbalance control device uses three A relay and three thyristors are connected in parallel to form a composite switch. The purpose of th...

AI Technical Summary

Problems solved by technology

[0005] (1) Increase product cost, which is not conducive to the popularization and application of commutation-type balancing devices;

[0006] (2) The large volume of CT is not conducive to the integration of the entire product on the circuit board, and the miniaturization of the product cannot be realized;

[0007] (3) When the current on the load side is very small or zero, this method cannot judge the state of the relay

Images