Initial Transient Recovery Voltage

Summary

The transient recovery voltage (trv) which appears at the opening of a circuit breaker is dependent on the lumped and distributed impedances of the elements of the network and busbars. It is important to determine whether the low impedances of the bars, or the presence of small capacitances connected to the bars, influences the breaking. It is intended to show how the different elements and arrangements of a station may be taken into account and how they may influence the trv. Due to the short lengths of these elements, the time under consideration is very short, less than 1 Ns; consequently, special attention will be given on the representation of the impedances together with a description of possible methods to study this phenomenon.

A brief survey of the results obtained by a working group of CIGRE gives the main results and a simple method for evaluation. Simple estimates of the influence of the resistance of an arc permits a discussion of the true importance of the initial transient recovery voltage (itrv) in the network or in a test-station.