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Szybkozmienne przepięcia łączeniowe w rozdzielnicach izolowanych gazem SF6 (GIS)

Karolak Janusz

Wiadomości Elektrotechniczne

2019

R. 87, nr 9

26--30

Omówiono zagadnienia powstawania bardzo szybko zmiennych przepięć w obwodach głównych (VFTO) oraz w osłonach (TEV) rozdzielnic z izolacją gazową (GIS), występujących podczas niektórych operacji łączeniowych wykonywanych łącznikami zainstalowanymi w GIS. Na podstawie danych literaturowych oszacowano poziomy zagrożeń izolacji rozdzielnic wywołane tymi zjawiskami oraz scharakteryzowano środki stosowane przez producentów do ich ograniczania.

In the article there are discussed the appearing of VFTO in main circuit of GIS and transient voltage in their enclosure (TEV) during some switching operations. Based on literature data it was estimated the level of threatening the GIS isolation by these phenomena and characterized countermeasure used by the producers for limiting them.

Multi-spark modeling of very fast transient overvoltages for the purposes of developing HV and UHV gas-insulated switchgear and of conducting insulation co-ordination studies

Szewczyk M.

Bulletin of the Polish Academy of Sciences. Technical Sciences

2017

Vol. 65, nr 6

871--882

Very fast transient overvoltages (VFTO) originate from steep voltage breakdowns in SF6 gas that are inherent to operation of any switching device of the gas-insulated switchgear (GIS) type. For power stations with voltage ratings exceeding 500 kV, the ratio between equipment rated- and withstand-voltage levels becomes relatively low, which causes the VFTO peak values to reach the component’s insulation withstand-voltage levels, thus becoming a design factor for high- and ultra-high voltage GIS. While well-established approach to VFTO analyses involves only single VFTO events (the so-called single-spark approach), there is often the need to analyze the entire VFTO generation process, for which the multi-spark approach to VFTO modeling is to be employed. The multi-spark approach allows one to evaluate the VFTO impact on the GIS disconnector design along with the impact of the VFTO on selection and dimensioning of the VFTO damping solutions. As the multi-spark approach to VFTO modeling is now being increasingly used in UHV GIS developments as well as for the insulation co-ordination studies of power stations, the present paper is motivated by the need to report on the VFTO multi-spark modeling approach and to lay a common ground for development works that are supported extensively with VFTO simulations. The paper presents physical assumptions and modeling concepts that are in use in such modeling works. Development of the multi-spark GIS disconnector model for VFTO simulations is presented, followed by an overview of examples of the model application for the GIS development works and for insulation co-ordination studies.