Voltage distribution of 220 kV GIS under different lightning impulse

Because of its excellent performance, GIS is widely used in GRID. After produced, manufacturers will assess the insulation of GIS by LI. On the other hand, the power sector will use OLI for on-site testing. The distribution of breakdown voltage on the nodes inside GIS induced by OLI or LI is the base of test result analysis. In order to master the distribution under the two impulses, in this paper, the numerical simulation software ATP EMTP is adopted to simulate the wave propagations in a 220 kV GIS under the two lightning impulses, the voltages on internal nodes induced by the two impulses are obtained and compared. The results show that there will be higher overvoltage under OLI than that under LI. As the distance between measuring point and entrance increasing, the voltage on node drops and the distortion decreases. The results of this paper provide data support for the on-site testing of GIS and judging the insulation of equipment.