Short-circuit fault current limiter

Abstract

Disclosed a short-circuit accidence amperite relates to the accidence amperite of power transmission and distribution network. The invention is characterized in that: it serially connects a current limited resistance an a parallel connection circuit with solid switch on the current limited inductance (common inductance or superconducting inductance) of present bridge short-circuit accidence amperite, and parallel connects a diode (reverse parallel connection) and a afterflow circuit serially connected to the resistance with the current limited inductance, to form said short-circuit accidence amperite. The added afterflow circuit can reduce the A. C. power loss and the back-pressure of current limited inductance. And it utilizes the hysteresis comparison control strategy to realize the switch of current limited resistance. In addition, the provided two connection in series-parallel structure of switch tubes and limited current resistance can meet the demand of high voltage of power network. The invention can limit the peak and the steady-state value of accident current. And said amperite has higher current limited ability, lower effect on the circuit, while it can improve the power quality of power network, and the stability, the safety and the reliability of high voltage or super-high transmission power network.

Description

technical field [0001] The invention relates to a short-circuit fault current limiter, in particular to a fault current limiter for transmission and distribution networks. Background technique [0002] With the rapid development of the national economy, the society's demand for electricity continues to increase, which drives the continuous development of the power system. The capacity of single machines and power plants, the capacity of substations, and the load of cities and industrial centers continue to increase, which makes the interconnection of power systems , the level of short-circuit current in the power grid at all levels is increasing continuously, and the destructiveness of short-circuit faults to the power system and its connected electrical equipment is also increasing. Moreover, while the demand for electric energy is increasing day by day, people also put forward higher requirements for power quality, power supply reliability and security. However, the trans...

AI Technical Summary

Problems solved by technology

[0004] However, there are still many deficiencies in the solid-state short-circuit fault current limiter. Its current-limiting inductance (L0) will only be connected in series with the grid to achieve current limiting when the grid current reaches the inductor 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 connected in series with the current-limiting inductor 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; the bridge composed of thyristors needs to increase the controller, which increases the system cost and reduces the reliability of the system

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