Partial Discharge Monitoring System For Power Transformer Based On Ultrasonic

The power transformer is an important equipment of power system and its partial discharge (PD) monitoring and diagnosing are very importance for the security of power system . Through consulting domestic and foreign documents about PD monitoring with ultrasonic , a system is brought forward , which construct with the partial discharge monitering system for power transformer based on ultrasonic . The system is based on the program Condition Monitoring and Diagnosis System of Power Transformer which is a sub system of the Hydro Power Plant Optimal Maintenance Information System cooperated with the Gezhouba Hydropower Plant of China Yangtze Power Co. Ltd .The paper consists such research works as bellow : Accord to the charecteristics of the PD signal in transformer and the charecteristics of the ultrasonic , choose the sensor and design the data processing circurt board . Analyzing the insulation structure of transformer . considering the location method , select the suitable measure point . Realize the gathering program . Use fequency method and time domain to process the ultrasonic digit singal , catch the PD wave , caculate the time delay of ultrasonic . Using the Guess-Newton method to caculate the no-linear least squre , locate the PD source .Through plenty scientific experiments to the PD monitoring system , the monitoring system may monitor the PD signal of transformer and locate the PD source. The measuring mean error is very small and which may be acceptable in practice.The devolopment of the PD monitoring system proved the application of ultrasonic method in PD of transformer is effective ,but we can also see the shortcoming of Ultrasonic monitoring method . The further research works to be developed are also put forward .