Partial Discharge Location Method of Oil-Immersed Transformer Based on EFPI Sensor

The detection of partial discharge of oil-immersed transformer mainly includes pulse current method, ultra high frequency method and ultrasonic method. Among them, ultrasonic method has the advantages of safety, insulation and anti-electromagnetic interference. It is suitable for installation in the interior of oil-immersed transformer, PD online monitoring, and has a development prospect. In order to study the positioning method of partial discharge in oil-immersed transformer, an improved pressure balance optical fiber EFPI sensor is proposed and a positioning system of partial discharge in oil-immersed transformer is built. The results show that the improved pressure balance EFPI sensor is not affected by the difference of temperature and pressure, the error of detection signal can be controlled within 7%, and the positioning accuracy can reach centimeter level. The research in this paper can provide theory and method support for local discharge monitoring of oil-immersed transformer.