Short-circuit fault current limiter

Abstract

The present invention relates to a short-circuit fault current-limiter for power transmission and distribution network. It is characterized by that in the existent short-circuit fault current-limiter two inductors are series-connected, and said two inductors are respectively series-connected with switch device in rectifier bridge, and connected with one end of original current-limiting inductor so as to form star-shape connection. Said invention is simple in circuit structure, and is favorable for raising electric energy quality of electric network, and is favorable for raising stability, safety and reliability of high-voltage or superhigh-voltage power transmission system.

Description

Technical field [0001] The invention relates to a short-circuit fault current limiter, in particular to a fault current limiter for a transmission and distribution network. Background technique [0002] With the rapid development of the national economy, the society's demand for electricity continues to increase, which has led to the continuous development of the power system. The continuous increase in the capacity of single machines and power plants, the capacity of substations, and urban and industrial center loads has made the power systems interconnected. , The level of short-circuit current in all levels of power grids continues to increase, and short-circuit faults are becoming more and more destructive to the power system and its connected electrical equipment. Moreover, while the demand for electric energy is increasing, people have also put forward higher requirements for power quality, power supply reliability and safety. However, the transient stability problem of lar...

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Problems solved by technology

[0004] However, there are still many deficiencies in the solid-state short-circuit fault current limiter. Its current-limiting magnet (L0) is only connected in series with the grid to achieve current limiting when the grid current reaches the magnet current. It can only limit the fault current at the moment of short-circuit. The peak value cannot limit the fault steady-state current, and the current waveform distortion during the current-limiting process is relatively large; in order to compensate the grid steady-state current waveform distortion caused by the voltage drop of the switching device on the bridge arm, a bias power supply in series with the current-limiting magnet is generally used method

However, the current flowing through the bias power supply is often 2 to 3 times the grid current, and must meet the requirements of the current change in the non-fault state and the fault state. Therefore, the realization of the bias power supply has certain technical difficulties and high requirements. cost

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