759 / 2022-03-31 21:13:58

Evaluation of the aging state of XLPE cable water tree based on the return voltage method

XLPE cable,recovery voltage time-domain spectrum,Recovery Voltage Test System

Purpose/Aim

In order to realize the accurate judgment and analysis of the aging state of XLPE cable insulation water tree, the application of recovery voltage method in XLPE cable insulation diagnosis technology is discussed.

Experimental/Modeling methods

In this paper, a test system is first built to realize the test of the time-domain spectrum of the recovery voltage. The water tree aging samples of medium voltage XLPE cables with different aging were prepared by the combination of electricity and heat, and the power frequency dielectric loss, isothermal relaxation current time-domain spectrum and recovery voltage time-domain spectrum were tested for the unaged cable, water tree aging cable and water tree aging cable samples with intermediate joints. Through the analysis of test data, parameters such as power frequency dielectric loss factor, aging factor, initial slope of recovery voltage, peak recovery voltage and peak recovery voltage time are obtained.

Results/discussion

The test results show that the dielectric loss factor and aging factor increase with the increase of the water tree aging degree of the XLPE cable, and the change law of the initial slope of the recovery voltage curve is also the same. The recovery voltage increases with time. For the water-tree-aged cable samples with intermediate joints, the recovery voltage curve shows a change of first increase and then decrease, accompanied by the appearance of a peak value.

Conclusions

Through the comparison and analysis of the above results, with the dielectric loss factor and aging factor as the reference, it shows that the test of the recovery voltage method can better reflect the aging state of the XLPE cable insulation water tree.