Study On The Insulation Diagnosis Of High Voltage Cable

In the whole power system,the power distribution,high-voltage cable is essential equipment,and its insulation is effective to ensure the safety of power system operation of the key factors,the ultimate goal of this study is to find a current and high pressure Cable operation is the best match,the highest efficiency,the best effect of high-voltage cable insulation detection method,then this test method will need to proceed from the cable operating safety point of view,or the safe operation of the power system,can achieve the cable Failure to quickly and accurately diagnose and locate,so as to effectively avoid the high-voltage cable insulation caused by the entire power system failure.At present,China’s domestic high-voltage cable is mainly used for the cross-linked polyethylene insulation,which is the aging of the electric tree branch is the main cause of its occurrence of insulation defects,leading to the main reason for the defects of semi-conductive shielding,microporous,Excessive concentration of electric field.In this study,high-voltage cable defects in detection technology and methods for the timely detection of high-voltage cable insulation failure and defects are very helpful.This research results to measure the polarization current affects polarization voltage,polarization time and humidity factors,according to the experimental results,we see a single dielectric performance in the linear characteristics of the good time to polarization and polarization current curve will continue to increase in the polarization voltage slow upward shift.From the angle of depolarization and polarization time,we find that when the polarization time and depolarization time is relatively long,the insulation aging information can reach the _maximum limit.Once the insulation cable is wet,the polarization and polarization current will increase correspondingly.From the measured aging curve,we can get the specific model parameters of the cable insulation.Through the analysis,we can see the circuit model the time constant of the _minimum and _maximum relative capacitance and resistance to aging as characteristic quantity,and between the _maximum time constant corresponding to R_max,C_max can effectively reflect the aging phenomenon occurred on the insulation paper,and between the _minimum time constant corresponding to R_max,C_max can reflect the the aging of insulating oil.After the aging of the cable insulation,the depolarization current of this study will also appear obvious shift,showing the aging characteristics of C_max,C_min,R_max,R_min decrease.In fact,the polarization current method has been widely used in the field of stator insulation,transformer insulation and so on.However,this method is a new application in the diagnosis of cable insulation.The depolarization current method is a nondestructive dielectric evaluation technique,which has great development space and application superiority in the field of the measurement of cable insulation.