Busbar residual voltage maintaining device

Abstract

The invention discloses a busbar residual voltage maintaining device. The busbar residual voltage maintaining device comprises a Rocco coil, a measure and control unit, a disconnecting switch, a current converter, a microcomputer integrated protection device, a current-limiting impedor and a current transformer; the Rocco coil is connected with the measure and control unit, the current converter and the disconnecting switch separately, the disconnecting switch is connected with the current transformer through the current-limiting impedor, the measure and control unit and the current converter are connected in parallel and then connected with the microcomputer integrated protection device, and the microcomputer integrated protection device is connected with the current transformer. According to the busbar residual voltage maintaining device, the precise time that a three-phase current crosses a zero point can be quickly and precisely predicted through a high-speed digital potentiometer arranged in the Rocco coil, a signal is sent out before each phase of the current crosses the zero point, accurate brake separating and disconnecting can be achieved when the currents approach the zero point through the disconnecting switch, short-circuit currents are converted to enter a deep current-limiting impedor, the short-circuit currents are limited, and the short-circuit current amplitude value is greatly decreased.

Description

【Technical field】 [0001] The invention relates to a current limiting device, in particular to a busbar residual pressure maintaining device. 【Background technique】 [0002] As we all know, when a short-circuit fault occurs in the power system, the short-circuit current is generally more than ten times the rated current, which causes great harm to electrical equipment such as transformers, generators, circuit breakers, and transmission lines. , the power load has risen sharply, and the capacity of the main transformer has also increased accordingly. The short-circuit current faced by the power grid system of various enterprises has approached and reached the maximum use limit of the load vacuum circuit breaker. The breaking capacity of the load-side vacuum circuit breaker is insufficient, and the transformer is resistant to short-circuit current impact Insufficient capacity design and other issues seriously threaten the safe operation of enterprises. Faced with today's proble...

AI Technical Summary

Problems solved by technology

[0002] As we all know, when a short-circuit fault occurs in the power system, the short-circuit current is generally more than ten times the rated current, which causes great harm to electrical equipment such as transformers, generators, circuit breakers, and transmission lines. , the power load has risen sharply, and the capacity of the main transformer has also increased accordingly. The short-circuit current faced by the power grid system of various enterprises has approached and reached the maximum use limit of the load vacuum circuit breaker. The breaking capacity of the load-side vacuum circuit breaker is insufficient, and the transformer is resistant to short-circuit current impact Insufficient capacity design and other problems seriously threaten the safe operation of enterprises. Faced with today's problems, many enterprises use high-impedance transformers to limit the short-circuit current of the system, but increasing the impedance of the transformer does not finally solve the problem of current-limiting depth, and the electric power is reduced very little. It also brings active and reactive power loss, and the investment cost rises. Therefore, we propose a busbar residual voltage maintenance device