Modified SVR Prediction Method of Transient EMI based on Theoretical Simulation and Experimental Analysis

The very-fast-transient-overvoltage(VFTO) generated by the operation of gas-insulated switchgear (GIS) is an important threat to the secondary-side equipment. In order to investigate the generation mechanism, a distributed parameter model by ATP-EMTP software was established to simulate the transient EMI. On the basis of theoretical simulation, an experiment was addressed to test EMI of secondary-side equipment. The test results indicated that theoretical simulation was reliable and the interference experienced by the secondary-side equipment was inversely proportional to the cable length, in addition Spearman rank correlation method was adopted to analyze the linear correlation between interference voltage at the secondary side and the breakdown voltage at the primary side. A modified support vector regression method was proposed to conduct quantitative analysis and prediction of the maximum interference level at the secondary side. By comparison with the practical tests under a 220kV GIS benchmark, the predicted precision of proposed method could achieve 98.6%. This investigation could provide technical support for EMI testing, analysis, and suppression of integrated primary and secondary equipment in substations.