Suppression of Fast Transient Overvoltage during Gas Disconnector Switching in GIS

Abstract

This paper describes the suppression of the transient overvoltage caused by gas disconnector switching of a small capacitive charging current in a gas insulated switchgear substation. The overvoltage is suppressed by the insertion of a resistor with an appropriate value during the switching. A scale model gas disconnector with the resistor is developed. The overvoltage suppression effect and the charging current breaking capability of the gas disconnector are experimentally confirmed. A prototype ultra high voltage gas disconnector is trial manufactured and tested.

Analysis of Magnitude and Rate-of-rise of VFTO in 550 kV GIS using EMTP-RV

“…Even though their magnitudes are lower than Basic Insulation Level (BIL) of the system, they contribute to the aging on the insulation of the system due to their frequent occurrences. Also, VFTO can influence on the insulation of other GIS equipment such as transformers [9][10][11][12][13]. Hence, it is necessary to estimate the magnitudes and the rate-of-rise of VFTO generated during switching operations for insulation coordination of GIS components.…”