Transient recovery voltage considerations in the application of medium-voltage circuit breakers

Abstract

Medium-voltage circuit breakers can fail to interrupt three-phase fault currents when power systems have transient recovery voltage (TRV) characteristics which exceed the rating of the circuit breaker. This paper examines the application of 13.8-kV generation and load switchgear for an oil refinery in which circuit parameters as originally designed would have exceeded the 13.8-kV circuit breakers' TRV ratings had corrective measures not been taken. This paper illustrates this case and discusses the basis of TRV, how TRV is assessed, and alternative actions taken to bring circuits to within the 13.8-kV circuit breaker ratings.Index Terms-EMTP, medium voltage circuit breaker, transient recovery voltage.

Mitigation of Transient Recovery Voltages using the Supercapacitor (Dept.E)

“…The circuit breaker contacts movements have influence on TRV, as it caused the insulation gap stress and arcing in the interrupting medium [10,11]. Following current extinction, the interrupting media is trying to return from a conduction state to an insulator state [12,13].…”

“…Restrikes are really dielectric breakdowns and can occur anytime during the TRV cycle, although usually they are associated with breakdowns later in the cycle (say tens to hundreds of microseconds) when the TRV has sufficiently high magnitude. Such an event is akin to a lightning flash-over across an insulator [10,16].…”

“…ATP is a computer program that allows an electrical system to be modeled and analyzed in the time domain, referred to as the electromagnetic transients program (EMTP). The program solves the system equations numerically in the time domain and the values of the TRV are determined for specific time instants within a user-specified simulation time [9,10].…”

Monitoring and measurement of high‐frequency oscillatory transient recovery voltage of circuit breakers

“…Current continues to flow in the new ionised gaseous medium until it reaches its zero-crossing instant. Within microseconds after current zero, the response of the power system on each side of the CB to the sudden change in current is different [1][2][3][4][5][6][7][8][9]. Accordingly, different voltages will be produced on CB contacts and this will result in a high-frequency transient oscillating voltage, known as transient recovery voltage (TRV).…”

Transient analysis of the 161 kU Taiwan‐PengHu submarine power cable system

“…References [5][6][7] should be referred for the rating structure, symmetrical current basis-referred ratings and related required capabilities, and application guides of TRV for AC High-Voltage CB. Reference [8] should be referred for the TRV considerations in medium voltage CBs.…”