Abstract
This paper has investigated the basic characteristics of switching surges in a gas-insulated substation and induced surges to a control cable based on EMTP simulations. It has been found that a switching surge voltage on the core conductor of a gas-insulated bus (GIB) tends to increase and the oscillating frequency becomes lower as the number of spacers increases. The maximum switching overvoltages become greater at the nodes nearby an operating disconnector (DS)/circuit breaker (CB) and become smaller at the source side. An induced surge to a control cable tends to increase as the parallel length of the GIB and the control cable increases. However, in the case of an open-circuited GIB, there exists a length which gives the highest voltage. A transient current becomes very large if a voltage transformer (VT) or a spacer is installed right next to an operating CB or DS, although this current does not affect the induced and VT transferred surge to the control cable. Also it is observed that a ramp wave voltage causes polarity reversing of a transient voltage on the GIB tank and the control cable.
