The effect of cable structure on space charge formation

An experimental investigation of space charges in LDPE (low-density polyethylene) and XLPE (cross-linked polyethylene) cables with different semiconductor layers is presented. The space-charge distribution was investigated using the field probe technique as a direct method. It was found that the structure of the semiconducting layers as well as the voltage polarity of the conductor have a marked effect on the space-charge distribution. The results provide direct experimental evidence on the polarity of space charges formed in HVDC (high-voltage, direct-current) cables. Their distribution helps to explain the reduction of the breakdown voltage that occurs on polarity reversal.<
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