Calculation method of hot spot temperature of isolation switch based on improved heat path model

The isolation switch is one of the most commonly used high-voltage electrical equipment in the power grid,and its stability and service life directly affect the operation of the power grid. The fast calculation method of the hot spot temperature for isolation switch is an important contents of on-line monitoring. However, the numerical calculation method of the thermal field distribution commonly used currently has a slow calculation speed, complicated modeling and change calculation conditions, and is difficult to apply. Therefore, this paper proposes an improved method for calculating the hot spot temperature of an isolating switch based on a thermal circuit model, which can better balance the accuracy and calculation speed. This article analyzes the GW16-550 outdoor high-voltage AC isolating switch. The calculation results show that the hot spot is located at the contact point of the contact. Under the rated conditions, the hot spot temperature is about 20 K higher than the ambient temperature. The hot spot temperature decreases with the increase of wind speed, and changes significantly at low wind speeds. Hot spot temperature is directly proportional to ambient temperature and service life. This research provides support for the research of hotspot temperature for isolation switch, and has certain practical value.