Study Of Transmission Line Protection Based On Parameter Identification

Traditional distance protection using fault time ratio of voltage and current, namely measuring impedance, characteristic of changes along with changes in voltage and current at the same time, judge or external fault in the region to achieve protection. For measuring impedance response the distance from the point of failure to protect the installation from non-electrical quantities, their protection from the influence of operation mode. But measuring impedance is the impedance angles contain resistance and reactance components,tuning very trouble. By analyzing the proposed protection algorithm of parameter identification of strengths and weaknesses, based on generalized algorithm for parameter identification of proposed protection method.Thesis research and analyse the principle and algorithm for two-Terminal fault location in frequency domain, in the Matlab double power supply model is built. Taking into account the basic requirements for line protection can be obtained through direct fault distance to determine whether the protection action, this algorithm is simple and easy tuning and so on.Considering coupling there is a complex of three-phase fault component, first the time domain signal is decoupled. Using a new type of phase-mode transformation, take advantage of the phase transformation of single modulus value response to all types of benefits, protection against influence of fault types. Secondly, in order to eliminate the non-truncated integer and non-periodic spectral leakage caused by sampling errors influence of fencing, on the analysis of the basic theory of the Fourier transform, principle and windowed interpolation algorithm based on studies interpolating windowed Fourier algorithm for correction of fractional frequency spectrum, thereby improving the accuracy of protective actions.Study on line protection needs, use Matlab to establish Jingjintang 500 kV high voltage,long-distance transmission line simulation model. Fault type and fault resistance and lineparameters are respectively simulation under different conditions, and have achieved good results.