ASSESSMENT OF HV GIS VERSUS HV AIS CONCERNING THE RELIABILITY OF TRANSFORMER SUBSTATIONS

Differences in the function and the requirements of substations in high voltage systems as well as the different design criterions worldwide have led to many substation configurations. In transformer substations HV/MV of densely populated areas, which are more and more equipped with gas insulated switchgears (GIS), single busbar, double busbar, as H-scheme connected breakers, one-and-one-half breaker arrangement and polygon connection are often used configurations. In comparison to air insulated switchgears (AIS) GIS show a higher availability. For the configurations mentioned above, the influence of these different availabilities on the reliability of supply is examined. In particular, the indices mean interruption frequency and expected energy not supplied are used for comparison. It is shown, that the lower failure frequency of GIS leads to less interruptions of supply, whereas an assumed longer down time of GIS does not lead to a higher energy not supplied.