Research on the relationship between insulation resistance and temperature of oil-immersed transformer in extremely cold environment

Oil-immersed transformer is the earliest type of transformer developed in China, and it is also the type of transformer with the most network operation in China at present. Nowadays, the alpine region as an important power supply base in the country is becoming more and more important. How to ensure the safe and stable operation of power transmission lines in extremely cold areas, improve the stability coefficient and tolerance capacity of power grid in extremely cold environment, and minimize the loss of power grid caused by extremely cold conditions, it is increasingly urgent to build the emergency response and recovery system of power grid in extremely cold areas actively and actively cope with extremely cold environment. While at the same time in the design of oil-immersed transformer, the insulation test research work very early, but for the limitation of test conditions, the rules only provide above 5 °C oil-immersed transformer insulation resistance testing standard, for under 5 °C environment research was still in the stage of blank, can't meet the requirements of the equipment running status diagnosis extremely cold areas. Based on this, this paper firstly conducted a survey and analysis of the operation status of oilimmersed transformers in China, and then built a transformer insulation resistance test platform in extremely cold areas to observe the insulation resistance of transformers at low temperature, and summarized the rule of insulation resistance changing with temperature, providing data support for the development of related researches in the future.