Research On Characteristic Simulation And Monitoring Of Winding Deformation Of Power Transformer

Power transformer is one of the important equipments for the stable and economical operation of power system and is responsible for the task of transforming voltage and tranfering energy,its normal operating conditions has significant implications for the overall system operation.The transformer can be collided when being transported or installed,and shorted abruptly when running,which can lead to the winding deformed.The winding deformation is one of the familiar faults of the transformer,and it harms the power system’s secure operation. For the purpose of detecting the latent accidents in time,it becomes very important to diagnose the winding deformation. Frequency response analysis (FRA) is the simple and effective method for diagnosing winding deformation,it is presently being widely used in many countries.The main of this paper is to study how to detect and diagnosis transformer winding deformation based on frequency response curves.In this paper,it builds the two equivalent circuits of the transformer winding to simulate based sweep frequency analysis.One of the test models is injecting high frequencysweep signal from bushing tap,it is an on-line test menthod.The other one is injecting high frequency sweep signal from bushing guide,it is an off-line test method.Winding deformation faults were simulated based on the two equivalent circuits of the transformer winding.And based on the two equivalent circuits, frequency response curves and characterisitic were analyzed when we changed different location parameters.lt also studied the variation tendency of curves and compared the sensitivity to frequency response curves when parameters changed.In this paper,common faults were simulated through changing different parameters,such as axial deformation,radial deformation,overall shift,turn to turn short circuit etc.It analyzed comparatively the change of frequency response curves under the different kinds of deformation and summarized the variation tendency of curves.When monitoring transformer winding deformation on-line based on injecting sweep signal through high voltage bushing,the influence of bushing condition on frequency response curves was generally neglected,which will have impact on judging winding fault.lt simulated the change of frequency response curves under bushing faults, such as insulation damping,capacitance bulge,insulation aging,capacitance breakdown etc,and compared the different frequency response characteristics between winding deformation and bushing fault.