Abstract: Partial discharge test is one of the key test items of transformer field handover test,which can effectively solve the insulation damage of transformer which can not be found in conventional test items.The analysis and treatment methods were introduced based on an example of partial discharge fault during field handover test of 220 kV transformer.Firstly,the fault situation was introduced.Then,the external investigation and internal diagnosis of the transformer were carried out,and the type and location of partial discharge were determined by comparing the test results of normal wiring and support positioning wiring.Finally,the above test methods were verified by comprehensive analysis and test,and the treatment measures such as adjusting the head end insulation and adjusting the high voltage bushing were given.This paper gives a complete set of solutions to the problem of partial discharge fault,which provides a reference for the analysis of partial discharge fault during field handover test.