GENERATOR Single-phase Fault Analysis And Protection

Increase the capacity of generator stator ground protection put forward higher requirements, external power supply type stator ground protection because of its outstanding advantages, has the widespread application prospect. According to the external grounding protection of some problems in the practical application of20Hz power type stator, the theoretical analysis and simulation test.This paper summarizes the current situation of generator stator ground protection, analysis principle, several existing main protection scheme through comparing the advantages and disadvantages of various protection scheme, make the stick out a mile. Then, a comprehensive assessment of the main wiring way of large generator neutral point. Through the analysis of maloperation of generator stator grounding protection case, put forward to improve the reliability of measures of protection scheme.Through the analysis and schematic diagram of stator grounding protection of20Hz power supply, the method of the admittance criterion and the criterion of power frequency zero sequence voltage combination. The reason of residual voltage generated and its effect on protection scheme, and draw the protection of neutral zero sequence equivalent circuit diagram considering the residual pressure, using Matlab-Simulink to build the model, the corresponding parameter setting, simulation, the calculated by the simulation results of error measurement of grounding resistance of different residual pressure protection. In addition, considered from the protection of safe operation of generator angle, the stator turbine startup and shutdown process of grounding protection scheme for the corresponding improvements.Finally, according to the full wave Fourier algorithm is applied to the data window is too long, is proposed to extract the20Hz component by using the least square algorithm, effectively shortening the filtering time.