A Short-Circuit Fault Handling Method for Flexible DC Grid Based on Combined HVDC Circuit Breaker

Abstract

The invention discloses a short circuit fault processing method for a flexible DC power grid based on a combined-type high-voltage DC circuit breaker. The method can carry out the preset switching-off operation of the combined-type high-voltage DC circuit breaker in the power grid according to a preset threshold value of a set current transfer switch when a DC fault happens to one line in the DC power grid and before the positioning of the system fault is completed. After the fault positioning and detection are completed, the method carries out subsequent operation for circuit breakers at two ends of a non-fault line and a fault line, so as to achieve the isolation of a DC fault. Therefore, the method can effectively improve the cutoff potential of the combined-type high-voltage DC circuit breaker in the power grid. Compared with a conventional processing method, the method can effectively reduce the cutoff pressure of the circuit breakers at two sides of the fault line, reduces the design requirements for the circuit breakers, and reduces the investment for the circuit breakers, so as to effectively improve the application prospect of the combined-type high-voltage DC circuit breaker.

Description

technical field [0001] The invention belongs to the technical field of electric power systems, and in particular relates to a short-circuit fault processing method of a flexible DC power grid based on a combined high-voltage DC circuit breaker. Background technique [0002] As the global energy shortage and environmental degradation continue to aggravate, the development and utilization of renewable energy has gradually received extensive attention from countries all over the world. However, limited by the capacity of the power system, most of the renewable energy has not been effectively utilized, and the phenomenon of "abandoning wind" and "abandoning light" occurs frequently; on the other hand, wind power, solar energy and other new energy power generation are intermittent and random , which makes traditional power equipment, grid structure and operation technology more and more incapable of accepting ultra-large-scale renewable energy. In order to solve the problem of g...

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Problems solved by technology

[0006] The above-mentioned combined HVDC circuit breaker is more suitable for the application of DC power grid than the hybrid HVDC circuit breaker. However, the control strategy proposed in this document only relies on the circuit breakers at both ends of the faulty line to clear the fault when the DC line fails. The fault current required to be broken by the circuit breaker is relatively large, which increases the manufacturing cost of the circuit breaker, which undoubtedly reduces the application prospect of the combined high-voltage DC circuit breaker

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