Extra-high-voltage direct-current power transmission converter station protecting method

Abstract

The invention discloses an extra-high-voltage direct-current power transmission converter station protecting method which concretely comprises the following operation steps: a converter station control system collects signals of all circuit breakers in an alternating-current field 3 / 2 wire by a secondary system in a converter station and judges the final circuit breaker and the final line according to the on-off state of the circuit breaker; and when the final circuit breaker and final line state is generated, the valve block locked tripping function is started, and the whole direct-current system line is cut off. The power transmission converter station protecting method disclosed by the invention overcomes the defects of complex structure and more dependence on software performance in the prior art, optimizes the loop structure and ensures the safety of extra-high-voltage direct-current equipment.

Description

technical field [0001] The invention relates to a protection method for an ultra-high voltage direct current transmission system, in particular to a protection method for an ultra-high voltage direct current transmission converter station. Background technique [0002] The high-voltage direct current transmission system combines the rectification station and inverter station of high-voltage direct current transmission in one converter station, and completes the conversion process of converting AC to DC and then converting DC to AC at the same place. The structure of rectification and inverter, The facilities on the AC side are the same as the high-voltage DC transmission, which can realize asynchronous networking, better realize the interconnection of power grids with different AC voltages, and isolate the two AC synchronous grids, which can effectively isolate the mutual influence between the interconnected AC synchronous networks. The short-circuit current is limited, and ...

AI Technical Summary

Problems solved by technology

At this time, the voltage on the DC line will increase proportionally with the increase of the AC grid voltage, which may destroy the commutation process of the converter, thereby further increasing the voltage of the AC bus.

Moreover, short-term overvoltage is often accompanied by severe waveform distortion, which will endanger the insulation of equipment in the converter station

[0005] At present, in the protection system of the converter station of the DC system at home and abroad, there are mainly two implementation schemes for the final circuit breaker and the final line protection. One is to form a protective exit scheme by lapping the relay circuit. This scheme has complicated circuits and cumbersome wiring. There are many components; the other is to form a protection exit scheme through the trip matrix in the software. This scheme mainly depends on the operation of the software and is prone to malfunction and misoperation.

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