Hybrid DC transmission system fault handling device and fault handling method

Abstract

The invention discloses a hybrid DC transmission system fault handling device, which comprises an acquisition unit, a fault identification unit and a fault handling unit. The invention also disclosesa hybrid DC transmission system fault handling method. The DC voltage and the DC of the hybrid DC transmission system, the AC voltage of an AC power grid connected with an inverter converter station and a rectifier converter station and the voltage of a submodule capacitor of a voltage source converter in the rectifier converter station are acquired; whether the hybrid DC transmission system failsis identified; and if fault happens, the rectifier converter station is controlled to switch a DC instruction value and / or a DC voltage instruction value, and the inverter converter station is controlled to switch a trigger angle instruction value. Due to the above technical scheme, the DC transmission line fault in the hybrid DC transmission system can be effectively handled in a condition in which the converter is not locked, reliable fault ride through can be realized, fast DC power recovery after the fault disappears can be realized, the stability of the AC / DC transmission system can be better maintained, and the safety of the AC / DC transmission system is protected.

Description

technical field [0001] The invention belongs to the field of hybrid direct current transmission, and in particular relates to a fault processing device and a fault processing method for a hybrid direct current transmission system. Background technique [0002] HVDC systems can be divided into two types: conventional DC transmission systems (LCC-HVDC) based on thyristor technology and flexible HVDC systems based on fully controlled power electronic device technology (Flexible-HVDC). Among them, the conventional direct current transmission system (LCC-HVDC) has low cost, low loss, and mature operation technology. The inverter side is prone to commutation failure, strong dependence on the AC system, absorbing a large amount of reactive power, and large area occupied by the converter station. The new generation of flexible direct current transmission system (Flexible-HVDC) can realize the decoupling control of active power and reactive power, can supply power to the passive net...

AI Technical Summary

Problems solved by technology

After the DC line fault disappears, the converters on the rectification and inverter sides will first close the DC side switch, then re-close the AC side circuit breaker for pre-charging, and finally restore the power of the DC system, so that the entire system can be restarted and restored The time is long, usually at the second level, which is not conducive to the transient stability of the AC-DC transmission system

Since at least one end of the hybrid DC transmission system uses a voltage source converter and one end uses a thyristor converter, when the DC transmission line of the hybrid DC transmission system fails, the general thyristor converter adopts the processing method of the conventional DC transmission system, and the voltage source The type converter adopts the processing method of the flexible DC transmission system, so the restart recovery time of the entire hybrid DC transmission system is also relatively long, usually on the order of seconds, which is not conducive to the transient stability of the AC-DC transmission system

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