Converter station with resistive superconducting current limiter and DC circuit breaker and its DC fault handling strategy

Abstract

The invention discloses a converter station containing a resistive superconducting current limiter and a DC circuit breaker and its DC fault handling strategy. The breaking capacity of the DC circuit breaker under the existing technical conditions reduces the requirements for the breaking current of the DC circuit breaker in the multi-terminal flexible DC power grid; at the same time, the present invention utilizes the DC fault restart protection module and the superconducting current limiter bypass protection module , which solves the problem that the recovery speed of the resistive superconducting current limiter is too slow, making it possible to quickly restart the system after a DC fault; A complete DC fault handling and restart recovery strategy is proposed.

Description

technical field [0001] The invention belongs to the technical field of electric power transmission and distribution, and in particular relates to a converter station including a resistive superconducting current limiter and a DC circuit breaker and a DC fault processing strategy thereof. Background technique [0002] There are contradictions in geographical conditions between my country's energy production and demand, and it is necessary to transmit electric energy from energy-sparse areas to load-intensive areas through "west-to-east power transmission" and "north-to-south power transmission". So far, the high-voltage DC transmission system (Line Commutated Converter based HVDC, LCC-HVDC) based on grid commutated converters has become the main way of long-distance large-capacity DC transmission. However, decades of operating experience have shown that it has the following insurmountable inherent defects: (1) LCC needs to rely on AC power for commutation during the commutati...

AI Technical Summary

Problems solved by technology

However, decades of operating experience have shown that it has the following insurmountable inherent defects: (1) LCC needs to rely on AC power for commutation during the commutation process, but new energy power plants such as wind power and photovoltaics do not It has the ability to provide AC power, so this directly limits the application of LCC-HVDC technology in many new energy grid-connected occasions

(2) Similarly, due to the excessive sensitivity of LCC to AC voltage, the inverter side system at the receiving end is prone to commutation failure, resulting in a large amount of DC transmission power interruption; in the case of multiple infeeds, multiple DC lines simultaneously Commutation failure will cause serious power flow transfer, which directly threatens the safe and stable operation of the system

(3) LCC-HVDC technology needs to configure a large reactive power compensation device and a complex filter, which results in a large area of ​​the converter station and difficult site selection

According to the different impedance characteristics of the current limiter after the fault, the superconducting current limiter can be divided into two categories: resistive and inductive. Under the current technical conditions, the resistive current limiter relies on its small size and simple structure , has the most potential to be applied to flexible DC systems; although inductive current limiters have a faster recovery time, they have the disadvantages of large volume and complex structure, and are only used in AC systems

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