Transient thermal analysis of gas insulated switchgear modules using thermal network approach

Abstract

Abstract Thermal analysis of Gas Insulated Switchgear (GIS) modules is of utmost important to optimize their dimensions for higher current ratings. Temperature rise test simulation has to be carried out on GIS modules to ensure that the temperature rise of modules shall not exceed the allowable temperature limits. The analyses also help to estimate the time duration required for GIS modules to reach steady state temperature as per IEC 62271-102 and IEC 61869-2. In the present study, to conduct transient thermal analysis, a novel Thermal Network Model (TNM) has been proposed for gas insulated switchgear equipment of two important modules i.e., disconnector switch (DS) and current transformer (CT). GISmodules.m program is developed in the study to analyze effect of various parameters like type of material being used for HT conductor and enclosure, rated voltage, rated current and enclosure current on time varying behavior of temperature rise of conductor and enclosure. Finally, the temperature rise test has also been carried out on 245 kV and 420 kV GIS modules at rated current ranging from 3150 A to 4000 A. When the transient temperature measurements conducted on 420 kV DS and compared with the results obtained through proposed TNM based analyses, it is clear that temperatures are within difference of 3.3 °C for conductor and 1.2 °C for enclosure. Further, it is evident that the time taken for conductor and enclosure to reach steady state temperature is about 8–10 h depending on enclosure current magnitude and GIS configuration.