740 / 2022-03-31 20:29:31

Effect of X-ray on Partial Discharge of Bubbles and Scratches at Different Scales in XLPE Cables

X-ray, XLPE cable, partial discharge

IEEE ICHVE 2022 / 1-PAGE ABSTRACT

Effect of X-ray on Partial Discharge of Bubbles and Scratches at Different Scales in XLPE Cables

Ju KONG, Shusheng ZHENG, Zongheng ZHANG, Yan ZHAO, Xiaohu YAN

State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources (North China Electric Power University)

Author email



Purpose/Aim

Typical defects of XLPE cables include bubble defects, scratch defects, etc. X-ray can reduce the initial voltage of partial discharge and statistical delay of bubbles and scratch defects, which is beneficial to improve the detection sensitivity of small bubbles and scratch defects in cables. Due to the different shapes and sizes of bubbles and scratches existing in the cables in practice, there is a lack of research on the detectable size of bubbles and scratches under X-ray applied to the rated voltage of cables. Therefore, this paper studies the partial discharge of bubbles and scratches with different shapes and sizes in XLPE cables under X-ray.

Experimental/Modeling methods

Bubble defect models with different sizes and shapes were made on the actual XLPE cable body. Partial discharge is detected by pulse current method under power frequency voltage. In this paper, the bubble defects of 1 ~ 8mm in diameter are made, and the scratch defects of 10x1x1mm, 5x2x1mm and 5x1x2mm are made in the middle joint of XLPE cable. The step-by-step boost method was used in the test. When the target voltage was raised, X-ray was applied to the defect. If partial discharge occurred, the data of X-ray pulse and partial discharge pulse were recorded. If no partial discharge occurred, the boost was continued until partial discharge occurred and the data were recorded.

Results/discussion

The experimental results show that the initial partial discharge voltage and discharge repetition rate of bubble defects with diameter of 1 ~ 5 mm can be significantly changed by X-ray. For bubble defects of 5 ~ 8 mm and above, X-ray has no significant effect on the initial partial discharge voltage and discharge repetition rate. X-ray can significantly change the partial discharge starting voltage and discharge repetition rate of scratch defects with different shapes, and the PRPD spectra of scratch defects with different shapes are significantly different.

Conclusions

The following conclusions are obtained from the experiment: X-ray can improve the detection sensitivity of 1 ~ 5 mm bubble defects in XLPE cables, and provide reference for the detection of micro bubble defects in XLPE cables.