The Fault Analysis Of HVDC System And The Study Of It’s Transmission Line Protection Scheme

In recent years, HVDC transmission technology developed very rapidly which has theability of transmit power of long distance, high capacity and low loss, the line is cheap andthe control performance is good.HVDC transmission technology has gradually become themain method to solve the problem of high voltage, large capacity,long distance transmissionand power grid interconnection, and HVDC transmission become the hot spot of the electricpower construction of our country because of the power of west to east, north and south forthe national network.With HVDC transmission play a more and more importance role inpower grid, how to enhance the security and reliability of the system has become a emergencyproblem to solve, so it is necessary to make a simulation study of the protection and controlmode characteristics of HVDC transmission system, analyzes the fault characteristic andimprove protection scheme further.This paper firstly introduces the general situation of HVDC transmission projectsincluding DC transmission system’s development, structure and power transmission means, andthen the paper builts a simulation model of the bipolar12pulse HVDC system on the basis ofthe CIGRE DC power transmission international standard test system by using the simulationsoftware PSCAD/EMTDC. The operation mode, typical faults of converter station and andDC transmission line fault in HVDC system are simulated and studied its faultcharacterization based on this model.By againsting the evelopment trend and current situationof line protection at home and abroad the paper analysised the principle of traveling waveprotection which basis of the transient fault component, the paper researched and analysisedthe criterion principle of ABB and SIEMENS’s DC transmission line traveling waveprotection and comparing the protection’s performance, discussed its application is discussed.Finally, combined with the existing traveling wave protection of HVDC project, put forwardspecific line protection configuration which mainly to traveling wave protection with thedifferential under-voltage protection and line differential protection and build model throughthe PSCAD/EMTDC software based on the HVDC model, then the scheme is simulationanalysised and verificationed. At the end of the paper the results towards these researchmentioned above are concluded and the direction of further work is pointed out.