Insulation aging evaluation method for 110kV XLPE high-voltage cable

Abstract

The invention discloses an insulation aging evaluation method for a 110kV XLPE high-voltage cable. The method comprises the following steps: testing polarization current and depolarization current ofthe high-voltage cable in a polarization process and a depolarization process through polarization-depolarization current (PDC); obtaining a low-frequency dielectric loss factor under the corresponding polarization voltage according to the obtained polarization current and depolarization current; and evaluating the insulation performance of the high-voltage cable by taking variation of the low-frequency dielectric loss factor under different polarization voltages as a characteristic quantity for representing the insulation aging of the cable. Thus, the insulation aging state of the high-voltage cable can be diagnosed efficiently, and reflected more accurately, the sensitivity is high, and the method can be widely applied in the field of cable insulation aging diagnosis in future.

Description

technical field [0001] The invention belongs to the field of electrical technology, and relates to a power cable insulation diagnosis technology, in particular to a method for evaluating the insulation aging of a 110kVXLPE high-voltage cable. Background technique [0002] Under the joint action of many factors such as mechanical stress, moisture, temperature and electric field, the insulation performance of the insulating body and accessories will gradually deteriorate, which will lead to a decrease in the insulation margin of the cable. Insulation breakdown, causing electrical accidents. In order to monitor the cable insulation state, it is necessary to carry out periodic insulation diagnosis on the cable. [0003] The insulation thickness of high-voltage power cables is thicker, the rated voltage level is higher, and the structure is different from that of medium-voltage cables. Therefore, traditional medium-voltage cable insulation diagnosis techniques (such as insulatio...

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Problems solved by technology

The isothermal relaxation current method has been applied to the insulation diagnosis of high-voltage cables, but it needs to fit and analyze the isothermal relaxation current curve, and the actual operation is complicated and unreliable

In addition, some scholars have also proved that the low-frequency factor of high-voltage cables is positively correlated with the aging state of their insulation, but their research is based on broadband dielectric impedance spectroscopy testing, which takes a long time to test and has problems in diagnostic efficiency.

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