Abstract:In order to solve the problem of short-term increase in electricity load due to population movement during the seasonal period, thus causing the 10kV oil-immersed distribution transformer (referred to as: distribution transformer) heavy overload operation or even burned out and other faults caused by electricity complaints. This paper combines the overload situation of distribution transformer in Guizhou region, analyses the overload capacity of distribution transformer, factors affecting the overload capacity, risks caused by overload operation and calculation of insulation life loss, sums up the basic characteristics of overload operation of distribution transformer, proposes overcurrent temperature rise test method to verify the overload capacity of the solution ideas and processing methods, and through the on-site test, verifies the feasibility of the processing methods, to provide a basis for rapid processing of distribution transformer overload operation; at the same time, combined with the plant insulation, the distribution transformer overload operation of heavy even burnt out faults caused by electricity complaints. At the same time, the application verification of using vegetable insulating oil to replace mineral insulating oil to improve the overload capacity of distribution substation is combined with the advantages of plant insulating oil with good electrical performance, high ignition point, wide source of raw materials and renewable, etc. The load performance before and after the replacement of the oil is analysed, and suggestions are made for short-, medium- and long-term governance.