665 / 2019-04-16 19:59:29

A New Method of HVDC Transmission Line Control and Protection

Control and protection;,HVDC transmission line,High resistance grouding fault,Firing angle

The control and protections of HVDC (high voltage direct current) transmission line include wave protection and current differential protection. If high resistance grounding faults happen in the HVDC transmission line, the above mentioned control and protection are unable to detecting the voltage and current wave, change rate. So all the protections would not act exactly and control the HVDC transmission quickly. A new method of HVDC transmission line control and protection is presented. This method applies the differential line current in each converter stations to start protection sequence. Besides, the firing angle of converter during the maximum resistance groundinging faults is considered as the tripping threshold. This controlling method could act quickly and eliminate the high resistance grounding fault. It takes advantage of the data existing in control and protection system, and would not require any hardware alteration. So this method is easy to implement. Through the simulation tests of RTDS (real time digital simulator) and real fault recorder data in HVDC project , this method has been proved to be sensitive and reliable when HVDC line faults occur.