Design Of On-line Detection System For Partial Discharge Of Power Transformer

The power transformer is one of the most critical electrical equipment in the power system and the hub of the transmission and distribution of power.The safe and stable operation of the power transformer directly determines the reliability and stability of the power supply system.The complex structure of the power transformer and its complex operating environment make it difficult to analyze reasons of a transformer failure.The transformer failures will incur immeasurable losses to the power system and even to society as a whole.Therefore,in-depth study of the causes of common faults in the transformer,real-time on-line monitoring of power transformer operation,on-line detection of transformer defects or potential failure are particularly necessary.Based on this,this article studies in depth the common faults of transformers,the on-line detection technologies of transformers and several commonly used on-line detection systems of transformers.According to statistical analysis,partial discharge is one of the most common causes of transformer failure.Various electromagnetic interference leads to partial discharge detection difficult,with the inaccurate positioning problems.In this paper,the principle of partial discharge of transformer,the influence of partial discharge,the non-electrical and electrical detection methods of partial discharge such as ultrasonic method,ultra-high frequency method,optical method,temperature method and pulse current method are studied thoroughly,and characteristic maps of signals of several typical partial discharge models.Information about the signal characteristics of the partial discharge inside the power transformer is obtained.In order to detect partial discharge of transformers,this paper designs a combined detection system of partial discharge of transformers based on ultrasonic method and UHF method.The development of ultrasonic sensors and UHF sensors are mainly analyzed and demonstrated as well as the design of signal processing module with its circuit simulation.Finally,it is verified by experiments that the designed partial discharge detection system has certain practicality and reliability.