Research On On-line Monitoring System Of Partial Discharge In Converter Transformer

Converter transformer plays a pivotal role in converter substation and is a very important electrical equipment in power transmission and transformation.If the converter transformer fails,some or all of the system will stop running,or even cause serious power failures.The insulation failure of internal connection,valve side winding and outlet bushing of converter transformer is one of the important reasons for the insulation failure of converter transformer.Therefore,the on-line monitoring of partial discharge on the operation state of the converter can timely find the early hidden trouble,which is of great significance for the evaluation,maintenance and safe operation of the converter insulation state.This paper summarizes the research status of partial discharge in converter transformers at home and abroad,and according to the partial discharge characteristics of converter transformers,designs an online partial discharge monitoring system for circulation transformers.The system mainly uses high-frequency and ultra-high-frequency sensors,especially focusing on the high-frequency sensor developed for on-line monitoring of local discharge in station area,to effectively grasp the insulation status of transformer;and uses different monitoring methods such as ultra-high-frequency local discharge of transformer oil valve,high-frequency local discharge of transformer casing terminal screen,high-frequency local discharge of transformer core clamp ground wire,etc;to apply waveform identification and atlas Identification,polarity identification and other technologies can solve the problem of anti-interference in the local discharge monitoring of the rheological casing,and improve the accuracy of the local discharge type identification of the online monitoring system through the research of the local discharge diagnosis technology based on the deep learning.In order to verify the feasibility of the system,the system is used to monitor the partial discharge fault of the circulating current transformer on site,and the better detection results are obtained.Compared with the traditional monitoring methods,it is more suitable for the on-line monitoring of the converter transformer,which is conducive to improving the safety and stability of the power system.