Transformer zero-loss depth current limiting system

Abstract

The present invention discloses a transformer zero-loss depth current limiting system, comprising a depth electric reactor. The depth electric reactor comprises a measure and control unit, a Rocco coil, and a controller. Both the Rocco coil and the controller are installed on a busbar. A high-speed digital potentiometer is disposed inside the Rocco coil. A high-speed switch is disposed inside the controller. A signal output end of the high-speed digital potentiometer is connected to a signal input end of the high-speed switch, a voltage output end of the busbar is connected to a voltage input end of the measure and control unit, and an end of the busbar close to the Rocco coil is connected to a transformer, and an end close to the high-speed switch is connected to a load. The system can be used to fast and accurately predict an accurate time at which a three-phase current crosses a zero point, and a high-speed switch can be used to accurately open and cut off when the current is close to the zero point; and a short-circuit current converts current and enters a deep current limiting electric reactor, to limit the short-circuit current. According to the present invention, system impedance is increased, a breaking current of a load side circuit breaker is further reduced, and manufacturing cost is lowered.

Description

[0001] 【Technical field】 [0002] The invention relates to a current limiting device, in particular to a transformer zero loss deep current limiting system. [0003] 【Background technique】 [0004] 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. Fac...

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Problems solved by technology

[0004] 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 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 transformer zero loss deep current limiting system

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