Surge Analysis on the Tank of a Gas Insulated Line using Lumped Element Circuits

Abstract

Surge voltages evaluated by a digital analysis method, for example Electromagnetic Transients Program (EMTP) and by an analog analysis method (Transient Network Analyzer: TNA) are compared with experimental results on a scaled model of a gas insulated line. From the results, it is confirmed that the analog analysis method has a satisfactory accuracy and its computing speed is quite high. The error caused by the lumped element modeling of the gas insulated line is comparatively small, and the line is not necessary to be treated as a distributed parameter line. The lumped element model is advantageous to understand the mechanism of the transient characteristic of the induced transint voltage. A simple equivalent circuit of the gas insulated line is proposedand its accuracy is confirmed by a comparison with the calculated result obtained by an accurate line model. The transient overvoltages of the tank and across the insulated flange can be analytically calculated using the equivalent model.