Improved self-adaptive current-limiting direct-current solid-state circuit breaker and control method thereof

Abstract

The invention discloses an improved self-adaptive current-limiting direct-current solid-state circuit breaker and a control method thereof. The structure comprises a first bridge arm, a second bridge arm, a third bridge arm and a fourth bridge arm and an H bridge circuit formed by the first bridge arm, the second bridge arm and the fourth bridge arm, and a series branch formed by the first bridge arm and the third bridge arm is connected in parallel with a series branch formed by the second bridge arm and the fourth bridge arm. The control method for the self-adaptive current-limiting direct-current solid-state circuit breaker comprises the following steps of initialization, the case when a fault signal is detected, the case after a tripping signal is received, and the case afterthe fault disappears or is processed. When the iL is close to the idc, the main branches of the first bridge arm and the second bridge arm are switched on at the same time, then the load branch is switched on, and finally the main branches are switched off, so that the solid-state circuit breaker is completely recovered to prepare for the next fault. Compared with the prior art, the method is used for a multi-end flexible direct-current power grid, in particular to a direct-current power distribution and direct-current micro-grid with a lower voltage level; the on-state loss can be greatly reduced during normal operation; after a direct-current fault occurs, the circuit breaker can quickly recover to a normal operation state, and the processing capability of a secondary fault is ensured.

Description

technical field [0001] The invention relates to the field of DC transmission / distribution / microgrid, in particular to an improved self-adaptive current-limiting DC solid-state circuit breaker and a control strategy for the topological structure of the circuit breaker. Background technique [0002] The DC system has high control flexibility, high power supply density, good power quality, less loss than AC lines, no need for reactive power compensation equipment, and is suitable for various power sources and loads, making it widely used in the field of distribution networks prospect. The rapid development of voltage source converter (voltage source converter, VSC) and modular multi-level converter (modular multi-level converter, MMC) technology has promoted the engineering application of DC distribution network. However, the fault damping of DC distribution network is small, the propagation speed is fast, and the damage is great, which puts forward extremely strict requiremen...

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Problems solved by technology

[0008]Aiming at the problems of rapid fault current rise, high amplitude, rapid fault propagation and wide range of damage in the current flexible DC system, as well as comprehensive consideration of investment costs and operational safety, this paper The invention proposes an improved self-adaptive current-limiting DC solid-state circuit breaker and its control strategy, which can quickly and automatically limit the DC fault current before the circuit breaker protection trip signal is received, reducing the requirement for protection action speed; at the same time, the operating loss is low , no bias power supply is required, and has no effect on the stability of the normal operation of the system

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