Shortcircuit fault current limiter

Abstract

The invention provides a shortcircuit fault current limiter which comprises a circuit breaker CB1, a transfer current limiting unit and a current detecting unit. The current detecting unit is serially connected with the circuit breaker CB1. The circuit breaker CB1 is parallelly connected with the transfer current limiting unit, an assembly which is composed of the parallelly connected circuit breaker CB1 and the transfer current limiting unit. The output end of the current detecting unit is connected with the control end of the transfer current limiting unit. The current detecting unit detects fault current which flows over the branch circuit of the circuit breaker CB1 in a shortcircuit fault working condition. Furthermore a corresponding triggering switch in the transfer current limiting unit is triggered on, thereby switching off the circuit breaker CB1. A secondary winding of a coupling reactor is serially connected with a system line. Amplitude of the fault current can be quickly restricted, and system impact by the fault current is reduced.

Description

technical field [0001] The invention belongs to the field of current limiters, and more specifically relates to a short-circuit fault current limiter based on a coupling reactor. Background technique [0002] In recent years, with the rapid development of the power system, the short-circuit current level of the system has increased sharply, and the continuous increase of the short-circuit current level has caused serious consequences to the power grid and restricted the development of the power system. Therefore, effective measures must be taken to limit the short-circuit fault current. [0003] As a technical solution to limit short-circuit fault current, the fault current limiter can effectively limit the short-circuit current level in the power grid. Among them, the fault current limiter has the following advantages: on the one hand, it can reduce the dynamic and thermal stability burden of various high-voltage electrical equipment such as circuit breakers, and ensure th...

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Problems solved by technology

(3) Solid-state current limiter: switch-type solid-state current limiter, but the cost of this solution is relatively high, and the corresponding speed of the protection circuit is required to be extremely fast; resonant solid-state current limiter, however, this solution introduces inductance and capacitance components, Increases the possibility of system oscillations and overvoltages

(4) Arc current transfer type current limiter, however, in this scheme, a current limiting resistor is used to limit the fault current, and there is a problem of resistance heating under the current limiting condition

The above current limiting scheme has limited its application in practical systems due to various defects.

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