Abstract:On-site diagnosis method of partial discharge for transformer equipment based on ultrasonic associated with electromagnetic wave and vibration test is studied. According to the structure and running condition of transformer and HV reactor, the on-site partial discharge detection based on ultra high frequency method, ultrasonic method and vibration test is carried out. Taking HV reactor in 500 kV line for example, the methods for on-site dectection, signal analysis and fault diagnosis are proposed. The research is helpful in determining the partial discharge of transformer and HV reactor, diagnosing the fault type and its severity, and improving the on-site detection level of equipment partial discharge, especially serious suspension discharge.