Space charge distribution measurement in insulating material of enameled wire

Since the space charge accumulation sometimes enhances the electric field in an insulating material, it can be thought as a reason of unexpected PD (partial discharge) generation. Therefore, measurements of the space charge in the insulating layer of the winding are required. The space charge accumulation in the insulating material is usually carried out using the PEA (pulsed electro-acoustic) method. In this measurement, the space charge distribution in film shape sample was a research object. However, the properties of specially-made film samples may be different from those of the insulating layer with the actual configuration of the winding wire, and it is difficult to evaluate the actual influence of the space charge to the motor windings. In this research, we improved the PEA system which can be applied to measure the space charge distribution in the actual insulating layer of the winding wire. Using the developed system, we found that the space charge accumulated in the actual insulating layer by application of high voltage.