Double bus-powered PT secondary voltage switching circuit and protection circuit thereof

Abstract

The invention discloses a double bus-powered PT secondary voltage switching circuit and a protection circuit thereof. The protection circuit comprises a change-over switch and a plurality of connection wires, wherein the change-over switch comprises four groups of auxiliary normally open contacts; and each group of auxiliary normally open contacts include two contacts and are connected with corresponding connection terminals of the double bus-powered PT secondary voltage switching circuit through the corresponding connection wires. The change-over switch has a first working state, a second working state and a third working state, the first working state is a first bus switching gear, the second working state is a stopping gear and the third working state is a second bus switching gear. A voltage switching device can switch secondary voltage collected from a first bus PT or a second bus PT to output normal secondary protection measurement voltage and metering voltage through adjusting different gears of the change-over switch, so that misoperation of a high-voltage switch cabinet relay protection device and electric energy metering leakage generated by a voltage loss caused by poor closing of auxiliary switch contacts of isolation switches are avoided.

Description

technical field [0001] The invention relates to the technical field of PT secondary voltage switching protection for substation dual busbar power supply, in particular to a PT secondary voltage switching circuit for dual busbar power supply and a protection circuit thereof. Background technique [0002] In the high-voltage switchgear powered by double busbars, no matter whether the secondary protection measurement voltage or the secondary metering voltage is obtained, the secondary voltage from the I bus and II bus PT (mutual inductance) is switched through the voltage switch controlled by the auxiliary switch of the bus isolation knife switch The device is used to complete the acquisition, switching and output of the secondary voltage from the PT, and finally determine which section of the bus PT is powered by the secondary voltage. [0003] In the actual working process, the auxiliary switch of the isolating knife often has abnormal operation. For example, when the isolati...

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Problems solved by technology

[0004] In view of this, the present invention discloses a double-bus isolation knife switch secondary voltage switching circuit and its protection circuit to solve the problem of voltage loss in the double bus isolation knife switch auxiliary switch voltage switching circuit, which affects the correct operation of the relay protection device and the electric energy meter. Measurement Accuracy Issues

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