Simulation And Study Of Very Fast Transient Overvoltage In 500kV Substation GIS

With the rated voltage increase of domestic power system, VFTO caused by isolating switches for fully enclosed combination substation become more and more severely.Therefore, the influence of transient overvoltage must be consider while designing high standard and high pressure GIS equipment.This thesis thought from the angle of the device structure, equivalent substitution was carried out at different parts the element. Then VFTO caused by GIS substation internal isolation switch operation was simulated which refer to the task about analysis of the electric field simulation results, and on the basis of GIS components accurately calculating parameters and with 500 kV GIS substation as the research object. According to the simulation results, GIS fast transient process different voltage grade were analyzed individually, and the trend of GIS equipment key position VFTO waveform were investigated. The effect to VFTO was analyzed from multi-angle such as the GIS substation internal, external and various components. A GIS simulation model was established and the emphasis of calculation parameters was selected.Because VFTO peak transient voltage of GIS shell change within the scope of the dozens kV, which far less than the amplitude of VFTO, it will act little impact on GIS internal transient process. Therefore only consider the spread on GIS bus conductor and GIS shell transient voltage caused by high frequency, and analyze the interference voltage of secondary equipment while simulating VFTO. Because the VFTO are higher which exist in disturbance voltage amplitude and frequency that caused by common used capacitive voltage transformer secondary cable, it may affect the online detection and secondary protection system, and need to pay enough attention on.