Study On Relationship Between DC Corona Discharge And Air Relative Humidity Under Non-uniform Electric Field

The domestic and foreign research found that there is a close relationship between the corona discharge and atmospheric parameters,which influence of humidity on corona discharge is particularly significant.So study the influence of humidity on corona discharge characteristics may provide new ideas for the humidity measurement,form new theory,have an impact on the humidity measurement technology,which has important academic significance and practical engineering application value.This paper in summing up based on the existing achievements at home and abroad, using 10KV DC high voltage power supply and needle electrode uneven field structure to obtain stable corona discharge in the air,then collect the corona discharge signal through the device. Through extensive testing research and systematic analysis of the influence of atmospheric relative humidity on DC high voltage corona discharge characteristics.The main work and conclusions are as follows:This paper introduces the theory of gas discharge and corona discharge mechanism. On this basis,the function relationship between humidity and corona discharge current is deduced and theoretically analysis of air relative humidity and corona current exponential relationship conclusion.Using the corona discharge signal acquisition system of high precision acquisition of NI company and virtual instrument Labview,testing system on corona characteristics of needle needle electrode DC corona discharge.Through to write data processing software which simple processing of the collected original corona discharge data,then using the data processing method for secondary processing data,such as list method, graphic method, average method, the moving average method and so on,and finally through MATLAB curve fitting,intuitive to the influence law of humidity on dc corona discharge through the curve.According to the processed data,calculation and analysis the influence of relative humidity on needle-needle electrode of DC corona discharge,get the corona discharge characteristics change with humidity of the air law:When the input voltage is the same, with the increase of relative humidity, needle electrode DC corona discharge dark current rising exponentially.which consistent with the function relationship that theoretical derivation of humidity and corona discharge current; in this paper,in the same humidity, along with the increase of the input DC voltage, the corona discharge dark current with a linear increasing trend;Whether in wet or high humidity, high pressure or low pressure condition, with the passage of time, the dark current is gradually reduced, and the humidity is higher the more obvious the dark current, the lower the humidity dark current decline more slowly.According to theoretical and experimental analysis, the humidity measurement of corona discharge shows a strong sensitivity, faster response and reply speed,making use of the relationship between the corona discharge current and relative humidity can be used for the real-time and rapid gas humidity measurement,which has wide application prospect.