Reignition surges at reactor current interruption in cable-system GIS

Abstract

Both a I50MVA reactor current interruption test using a GIS on an actual 275kV cable system and a laboratory highfrequency current interruption test using a 300kV SF as circuit breaker were conducted. The results of these tests and their analyses, made simultaneously, enabled the calculation of reignition surges and the detection of high-frequency arc extinctions caused when the reactor current was interrupted by a GIS on a cable system and they also enabled an evaluation of voltage escalation caused at highfrequency arc extinctions.6 . g

An electric model of gas-insulated shunt reactor and analysis of re-ignition surge voltages

“…(1) where, C, :Inter-" capacitance, n: Turn number per section An equivalent circuit of a double diskcoil is shown in Fig. I@).…”

Modeling of gas-insulated shunt reactor for high-frequency surge analysis

“…The series capacitances of the windings are calculated using Eqs. (1) and (10) for the high-cell winding and the continuous winding, respectively. The capacitance of the winding to the ground is estimated by dividing the measured value of 600 pF of the winding model according to the height of the divided block.…”

“…When the surge voltage accompanying the switching operation of such a shunt reactor is to be analyzed, there must be an electrical model that can simulate the reactor for a wide frequency range, from the transient recovery voltage frequency of several kilohertz to the high-frequency surge produced when the redischarge occurs. Especially, it should be noted that the surge voltage generated in the redischarge has a high-frequency component from several hundred kilohertz to 1 MHz, depending on the situation [1,2].…”

Steep fronts at transient recovery voltages appearing with the interruption of inrush currents of transformers

“…Well-known overvoltages generated at the terminals of substation transformers at the time of switching include those due to (1) excitation current chopping in no-load transformers, (2) closing of no-load transmission lines, (3) reignition when interrupting a charging current on no-load transmission lines, and (4) reignition when switching weak charging currents by disconnecting switches. At transformer terminals, (1) and (4) are generally not high in terms of overvoltages; (2) is also not high in cable systems.…”

“…There might be almost no reclosing involved with a large overvoltage, in other words, reclosing with a voltage remaining on a transmission line. Regarding (3), should reignition occur, the terminal voltage of the transformer would not exceed the residual voltage for which the overvoltage frequencies are relatively low. This paper discusses the generation of a steep-front transient recovery voltage (TRV) appearing between circuit breaker electrodes when the transformer excitation inrush current is interrupted.…”