Hybrid DC circuit breaker for reducing reclosing impact and control method

Abstract

The invention provides a hybrid DC circuit breaker for reducing reclosing impact and a control method. The hybrid DC circuit breaker for reducing reclosing impact comprises a main through current branch, a main breaking branch and a reclosing damping branch, wherein the reclosing damping branch comprises multiple damping units, the multiple damping units are serially connected, each damping unit comprises a power electronic switch and a damping resistor, the power electronic switch and the damping resistor are in parallel connection, and the reclosing damping branch and the main breaking branch are serially connected and are then parallelly connected with the main through current branch for reducing secondary impact on the system in the case of reclosing at permanent fault. The circuit breaker of the invention can not only minimize the reclosing impact, but also accurately detect permanent fault with a high resistance property and realize flexible reclosing.

Description

technical field [0001] The invention relates to the technical field of power electronics, in particular to a hybrid DC circuit breaker and a control method for reducing reclosing impact. Background technique [0002] With the development of high-power power electronic devices, the DC transmission based on the voltage source converter, because its reactive power and active power can be independently controlled, without filtering and reactive power compensation equipment, can supply power to passive loads, and the voltage is extremely high when the power flow is reversed. It has become the main development direction of DC transmission. However, since there are no transformers and other equipment in the DC transmission line, the line reactance is low, and when a short-circuit fault occurs, the short-circuit current rises quickly and has a high amplitude. At the same time, there are a large number of power electronic devices in the DC transmission line. If a fault occurs and th...

AI Technical Summary

Problems solved by technology

The disadvantage of this recovery strategy is that when the reclosing is in a permanent fault, it will cause secondary damage to the system, which is not conducive to the safety of the system.

[0005] However, there is no research on how to reduce the secondary impact of the circuit breaker reclosing on the system. The relevant research mainly involves the limitation of the short-circuit current rise rate when a fault occurs. By adding a current-limiting circuit around the hybrid DC circuit breaker, The disadvantages of this prior art are: the current-limiting inductor is also put into operation during normal operation, which reduces the dynamic response speed of the control and increases the risk of voltage oscillation; when reclosing on a permanent fault, the current-limiting inductor can only limit the fault current The rate of rise is equivalent to buffering the closing, and cannot reduce the size of the fault current, so it cannot reduce the secondary impact of reclosing on permanent faults

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