Simulation And Experimental Study On Partial Discharge Ultrasonic Location Of Inner Transformer Windings

As the core of energy conversion in the process of power transmission and distribution,the reliability of transformer plays a very important role in the safe operation of power system.Partial discharge is the early manifestation of transformer insulation deterioration.The magnitude of discharge and fault location are closely related to the operation life of transformer.Insulation detection and fault location of transformer in operation is a difficult problem for the industry,especially when the insulation weak point of partial discharge fault occurs between transformer windings turns,it will be more difficult to detect and locate.In this paper,the finite element method is used to simulate the ultrasonic signal of partial discharge in transformer winding.The propagation law of ultrasonic signal in transformer winding is studied.The scheme of locating partial discharge in transformer winding by time difference location method is proposed,and the corresponding sensor arrangement scheme is obtained.The 35 kV transformer winding is customized and a new structure is used.The EFPI fiber optic sensor is tested in real object,and the accurate positioning results are obtained,which verifies the correctness of the simulation results and the feasibility of TDOA positioning algorithm.On this basis,the error analysis of the simulation positioning results is carried out,the causes of positioning errors are studied,and the corresponding improvement methods are put forward.The simulation models of transformer windings with different voltage levels are constructed.Type Ⅰ,the simulation positioning of partial discharge in windings is studied,and the sensor layout scheme of partial discharge positioning in transformer windings of different sizes is obtained.Through simulation and positioning research,it is verified that the time difference positioning method can be applied to the partial discharge positioning in transformer windings,and the results are more accurate,which provides anew method for the detection and positioning of the partial discharge signal in transformer windings.