Commutation failure acceleration protection method and system

Abstract

The invention discloses a commutation failure acceleration protection method and system, and belongs to the field of high-voltage / extra-high-voltage direct-current power transmission. The method comprises the steps of (1) configuring a commutation failure acceleration protection bipolar section, a monopolar section, a single-layer section and a single converter section; (2) configuring a power latch; (3) performing acceleration protection logic judgment by adopting a power value output by the power latch, the corresponding power constant value and the allowable maximum commutation failure frequency constant value, and when the specific commutation failure frequency exceeds the constant value frequency, outputting a corresponding protection action signal by the converter; and (4) selectively executing bipolar locking, monopole locking, single-layer locking or single-converter locking according to the action signals of the protection of each section in each converter. According to the invention, rapid protection can be simultaneously realized when continuous commutation failure occurs in bipolar, monopolar, single-layer and single-layer converters, and the purposes of timely removingthe faulty converter and ensuring safe and stable operation of a power grid system are achieved.

Description

technical field [0001] The invention relates to a commutation failure acceleration protection method and system, belonging to the field of high-voltage / ultra-high voltage direct current transmission. Background technique [0002] The commutation failure of the line commutated converter (LCC, Line CommutatedConverter) in the HV / UHV DC transmission system has always been an important factor affecting the safe operation of the large power grid. With the further improvement of the coupling degree of the current AC-DC system, the formation of "stiff It is particularly prominent under the pattern of "weak trade". [0003] With the increase of DC system capacity, when a single converter station fails, the impact on the system becomes stronger and stronger. The latest ±1100kV Jiquan UHV DC project put into operation has a double-pole rated transmission capacity of up to 12,000MW. If a single-pole (or single-layer) continuous commutation fails, the active power deficit will reach 6,...

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Problems solved by technology

However, according to the existing strategy, when continuous commutation failure occurs in only one pole (or single-layer or single converter), only the double-bridge commutation failure protection fast section can act to remove the fault after 2.6s. Sustained commutation failure for such a long time is very likely to trigger a chain reaction, causing the entire system to oscillate and even the power grid to collapse

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