Naslov
Evaluation of the risk of failure due to switching overvoltages of a phase to phase insulation

Autori
Xemard, Alain ; Michaud, J. ; Guerrier, A. ; Uglešić, Ivo ; Levačić, Goran ; Mesić, Miroslav

Vrsta, podvrsta i kategorija rada
Radovi u zbornicima skupova, cjeloviti rad (in extenso), znanstveni

Izvornik
Proceedings of IPST 2011 in Delft / - , 2011, 1-7

Skup
IPST - International Conference on Power Systems Transients

Mjesto i datum
Delft, Nizozemska, 14.06.2011. - 17.06.2011

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
phase to phase insulation, upgrade of overhead line, risk of failure, EMTP-RV

Sažetak
The upgrade of an overhead line (i.e. the use of an overhead line at a voltage higher than the voltage for which the line was initially designed) requires generally a careful consideration of the switching overvoltages both phase to ground and phase to phase. This last type of overvoltages is posing a specific problem because, for systems belonging to the second range of the IEC, the phase to phase switching withstand voltage of a self restoring insulation depends on the repartition of the voltage between the electrodes. When estimating the risk of failure of a specific air insulation due to switching overvoltages, an EMTP-like software is usually used to evaluate the constraints. Events causing switching overvoltages are chosen randomly and, for each of them, the overvoltages are calculated with EMTP. The risk of failure is deduced from the knowledge of the probability of these events (usually the switching time of a breaker), from the level of overvoltage obtained for each event, and from the withstand of the insulation. This approach is quite simple to implement for phase to ground self restoring insulation but it is less straightforward for phase to phase insulation because for each event considered, the over-voltages calculated with EMTP correspond to a different repartition of overvoltages between both electrodes. Therefore overvoltages due to different events are not directly comparable. In this paper we present an approach for the calculation of the risk of failure of a phase to phase self restoring insulation due to slow front overvoltages compatible with the use of an EMTP like software. The approach is illustrated by a practical example related to the upgrade of an overhead line from 245 kV to 362 kV.

Izvorni jezik
Engleski

Znanstvena područja
Elektrotehnika

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