Order Publications

Reference: ISH2015_268

ISH Collection

Study on The Shape Transformation of PD Fibrous Degradation Products in Oil-Impregnated Paper Insulation Under DC Voltage



Partial discharge (PD) has always been a critical threat to converter transformers. When PD happens, various degradation products will emerge within the oil-paper insulation system and accelerate the ageing process of the dielectrics. In this paper, a two-copper-electrode model that simulates oil-paper insulation among transformer discs was designed to study the motion and the shape switching phenomenon of PD degradation products under DC voltage. With the help of high-speed camera, four fibrous products of different shapes were spotted and analysed. Each shape of product corresponds to a specific PD waveform. Products of different shapes transform mutually. Based on this fact, a mechanical model was proposed to explain the transformation process. In the model four kinds of forces were taken into consideration, out of which the traction force turns out to be the critical force that determines the formation of free fibrous particles. Once the traction force becomes weak, products of pile-form and thread-form will fall off from the surface of the oil-impregnated paper. Out of four shapes of products, threadlike one is believed to be the most dangerous to the insulation considering about the high-amplitude PD it initiated. Free fibrous particle is the least severe one for the possibility that it will flee from the location of high electrical strength. Besides, the switching rate of pile-form and thread-form fibrous products and the applied voltage exhibits a positive correlation relationship.

File Size: 383,6 KB

Year: 2015

FREE free
Non member
FREE free

Your AccountYour Account

Password forgotten


may download free of charge all publications including most recent ones

Non Members

may download free of charge publications over three years old and purchase all publications

For any questions in connection with the on-line library, contact:


Publications and Edition Manager