In order to realize the accurate judgment and analysis of the aging state of XLPE cable insulation water tree, the application of return voltage method in XLPE cable insulation diagnosis technology is discussed. In this paper, firstly a return voltage time-domain spectrum test system is built. Under laboratory conditions, aging samples of medium voltage XLPE cables with different aging types are prepared by means of combined electric and thermal, which are subjected to power frequency dielectric loss, isothermal relaxation current time domain spectrum and return voltage time domain spectrum test. The test results show that both the dielectric loss factor and the aging factor gradually increase with the aging degree of the XLPE cable. Taking the dielectric loss factor and the aging factor as a reference, the change law of the initial slope of the return voltage curve is also the same. And for the water tree aged cable samples with intermediate joints, the initial slope of the return voltage curve is very large, accompanied by the appearance of wave peaks. It shows that the test of return voltage method can better reflect the aging state of XLPE cable insulation water tree.

XLPE Cable;test system;return voltage;isothermal relaxation current