A Case Study on Ablation Breakdown of High Voltage Cable Buffer Layer

The ablation of high voltage cable buffer layer has puzzled the field of high voltage cable for nearly 20 years. It has been studied that the development process of this kind of fault is that the buffer layer of high-voltage cable develops from whiteness, ablation to cable breakdown. More and more high-voltage cable related personnel pay attention to such failures. With the development of research, the reason and mechanism of this kind of fault are gradually clear. Based on a typical case of ablation failure of buffer layer of high voltage cable, this paper analyzes the failure phenomenon and mechanism. It eliminates the possibility that the buffer belt may be affected by moisture due to the water breaking out of the cable. The resistivity and moisture content of the buffer belt of different cable sections are tested, and the gap between the buffer layer and the aluminum sheath is measured, which verifies the theoretical analysis results. It is found that the volume resistivity and water content are both higher than the existing standards. The results of this paper lay the foundation for the further study of this fault type.