Abstract: The paper presents a kind of oscillating wave voltage test system based on oscillating wave theory and its research status at home and abroad and discusses its application in the withstand voltage test and PD detection of power cables. It is proved that the oscillating wave voltage and AC voltage have good equivalence. Compared with AC voltage and ultra-low frequency voltage (0.1Hz), it has some advantages such as shorter operating time and easy to operate and so on. It can find most kinds of defects in the XLPE cable effectively and does no harm to the cable.
Key words: oscillating wave voltage, XLPE power cable, withstand voltage test, partial discharge (PD)ime
The XLPE cable is widely applied in the electric system but it is extremely difficult to conduct the power frequency withstand voltage test on site. It becomes a key problem which needs to be fixed urgently. In the past, the DC withstand voltage test was used for oil-filled cable, minimizing the requirements for power supply. The XLPE electric cable has high insulation resistance and the voltage distributes differently at AC or DC. After the DC withstand voltage test, a large quantity of space charges left at the cable defect especially in the XLPE cable. After the cable is put into operation, space charges often cause insulation breakdown of cables. Studies have shown that it is not suitable to use DC voltage to carry out the withstand voltage test for XLPE cable. As for the ultra-low frequency (ULF) voltage, the test time should be long; the damage to cable insulation is big, which may cause new defects in the cable. The variable frequency resonant voltage generator can address the problem of power capacity. In addition, the test voltage and power frequency voltage have equivalence. However, its volume is large and it is heavy so it is difficult to realize on site.
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