Precise multi-dimensional temperature-rise characterisation of switchgear based on multi-conditional experiments and LPTN model for high-capacity application

As the power load increases, the capacity of switchgear becomes larger so the problem of overheating of switchgears becomes more significant. Whether the switchgears operate safely and reliably affects the reliability and economy of the entire power system. Different methods have been tried to study the thermal problems of switchgears. However, there are few experimental studies on the switchgear entity. In this study, a series of temperature rise tests were carried out on medium-voltage high-capacity switchgear to explore laws of temperature rise. First, five groups of multi-conditional experiments were carried out including changes of the load current, ventilation conditions and loop resistance. Then, multi-dimensional temperature-rise characterisation was analysed based on the experimental results and the relating theory. Finally, a circuit-based lumped-parameter thermal network (LPTN) model was developed by analysing the heat dissipation in switchgear and used to determine the steady-state temperature distribution of the switchgear. The model is verified by comparing the simulation results with the experimental results.