Application Research On The Transmission Lines Protection Based On Parameter Identification

Transmission lines are the sills of electric network. Line protection plays an important role in system stability and equipment security. Therefore, stability, safety and reliability running of line protection directly relate to the reliability of systems operation. Any error action of the line protection will cause great impact and losses to power system. Based on the above-mention reasons, the main research direction on line protection is to obtain superior performance and reliability of protection.The paper firstly introduces several typical existing line protections and their shortage, on the basis, a line protection using the principle of parameter identification is presented. The thesis is composed of several parts, i.e. the basic theorys of system identification, how to choose transmission lines simulation model, the principle of R-L line parameter identification and its algorithm establishment. Finally, the actual Puhong 500kV line double ended power supply system where fault occurred frequently and geographical conditions are poor is simulated and the related parameters are identified.The simulation results have verified the accuracy of the line parameter identification principle presented, and show this method is not only affected by system operational factor, transition resistance and system oscillation, but also can accurately work out the fault location, identify the system parameter and transition resistance. The method has good application prospect.