Study On On-line Corona Discharge Monitoring System Of EHV Transmission Lines

With the proposed of Intelligent Power System, UHV transmission network has beengradually formed. Our country is gradually expanding the scale of power transmission fromwest to east and improving the regional backbone network to enhance the development ofthe transmission with advanced technology which has large capacity, high efficiency,long-distance and so on, such as UHV. But at the same time, there are more and more powergrid accident flowing it. The frequency of insulation fault also increases everyday. So takeadvanced detection technique, timely discovery and fore notice those phenomenon whichmaybe characterized possible insulation deterioration of instrument, it have importantreference value for the equipment maintenance, repair and also avoid power accident. Onthis basis, this paper carried out the research on one kind of online monitoring system whichuses ultraviolet pulses number to characterize the condition of equipment insulation.In the first part, it is a fundamental review of gas discharge theory that has been studiedand researched in-depth, which contains its basic conditions, discharge forms, the principleof UV-detection technology and its practical application. At the end of this part, the greatsignificance and unique advantages of testing the equipment’s insulation states based on theUV-technology is illustrated.In the second part of this paper, a kind of corona discharge online monitoring detectionsystem is introduced, especially its’ composition and the role of each module. Besides this,UV sensor and its’ drive circuit, the characteristics of temperature and humidity sensorSHT71and its data collection are also discussed. What’s more, this paper not only discussedthe application of GPRS in the power system and its networking mode, but also completedthe PC monitoring software design with the LabVIEW and realized the communicationbetween LabVIEW and lower computer.In addition, through statistical analysis this paper completed the pre-processing ofexperimental data, and its’ power spectrum analysis of AR model at latter part. With theresults, we have one new reference to judgment the equipment insulation. In another part ofthis paper, one kind of equipment insulation condition assessment method based on fuzzyinference is involved, which could provide us one concrete insulating state index values, itwould be one important information for the equipment maintenance personnel. Finally, with the experimental verification, the corona discharge monitoring systemwhich is studied in this paper has many advantages, such as anti-interference ability, fastresponse, real-time online and so on. But it needs further study if we want to make it beuseful for practical engineering.