The document presents a study on estimating re-striking transient overvoltages in a 3-phase 132kV gas insulated substation (GIS). It discusses:
1) A MATLAB model was developed to simulate a GIS system comprising an input cable, spacer, disconnector switch, 10m busbar and load. Transient overvoltages generated during disconnector switch closing and opening operations and 3-phase faults were analyzed.
2) During disconnector switch operation, multiple re-strikes occur due to the slow contact speed, generating transient overvoltages. Each re-strike was modeled as a voltage collapse across the gas.
3) Simulation results show the magnitude and rise time of