Research And Design Of Partial Discharge Monitoring System For Transformer Based On Electro-acoustic Coupling

Transformer is a basic equipment to ensure the normal operation of the power grid system and guarantee the power supply reliability.When in the event problem or fault,the widespread blackouts will appear which influence People's daily life and the factory's production electricity,causing great economic losses.Due to the fact that current transformer partial discharge monitoring system's precision is relatively low,also with high rate of false positives,the development of perfect and reliable transformer partial discharge testing system is very important.Based on tne systematically inheriting and summarizing domestic and foreign research experience,in cooperation with the UHF sensor,HFCT sensor and AE sensor etc for partial discharge signal acquisition devices,and also the graphical programming language LabVIEW 7.1 as software platform programming,a set of electric and acoustic joint based electricity transformer partial discharge on-line detection system has been designed and developed.The system integrates the UHF monitoring,HFCT high-frequency current monitoring,AE ultrasonic monitoring,overcoming the traditional isolation system's in capable of relatively perfect monitoring on the partial discharge within the transformer which effectively improves the sensitivity of partial measurement,positioning accuracy and anti-interference ability.In the aspect of software,by using integrated modular design,the rate of systematic data caculation and anlysis with reliability can be aided for improvement.In addition,tne system is integrated with the internal structure of transformer,which can reduce the interference of the system to the electromagnetic balance of the transformer,improving the sensitivity and the anti-disturbance ability of the system.Based on the measurement on 3 underground 110/10 kv substation's main transformers by the presented system,the results show that the application of the electric and acoustic joint online monitoring system in the transformer partial discharge detection and analysis is feasible and effective,and various functions in the systerm have reached the design requirements,which can provides a large number of reliable data base for transformer's condition maintenance,and also provides new schemes and references for solving the problems of partical discharge testing of transformers.