Partial Discharge Characteristics In Oil Based On Multiband Microstrip Antenna

As an integral part of the power system,electrical equipment runs through all aspects of the system operation.Its importance is self-evident.As the precursor of insulation fault of electrical equipment,partial discharge gets full attention in the maintenance of system.The partial discharge detection of electrical equipment can detect the insulation defect of electrical equipment in time,nip in the bud,and reduce the probability and severity of accidents,ensure the safe and stable operation of equipment,improve the reliability and economy of power system operation.The generation and radiation mechanism of partial discharge UHF(Ultra High Frequency)signals are firstly analyzed and introduced,and the principle of UHF antenna reception is described.After theoretical analysis and a large number of experiments,partial discharge UHF signal in oil are selected as detection frequency band.Using monopole antenna combination,multi-band microstrip antenna is designed as partial discharge UHF detection antenna.Setted up the ultra high frequency detection platform in the laboratory,made four kinds of discharge models,simulated the needle-plate discharge,surface discharge,skid discharge and suspended discharge in oil,detected using developed multi band microstrip antenna.And focused on the model of needle-plate discharge,the influence factors of partial discharge correlation test on UHF antenna received by antenna.Including discharge air gap,discharge voltage,test distance and discharge medium.After the current UHF PD broadband and narrowband detection method research,multiband detection and produced antenna.After the performance measurement,the antenna performance is basically consistent with the simulation results.The antenna anti-interference,high sensitivity,small volume,meet the test requirements.In the experiment of four kinds of discharge models,there are differences in the frequency band distribution of the UHF signals tested by different discharge models.It is mainly reflected in the 400MHz~800MHz band,provideed the basis for partial discharge pattern recognition.Study on the factors affecting the ultrahigh frequency signal of needle plate discharge,the results show that increasing with discharge voltage,test distance,discharge gap and medium molecular density,the amplitude of the received signal of the multiband microstrip antenna gradually decreases.But the distribution of the signal in the frequency domain is basically the same.It can also be explained that this method can realize local pattern recognition.