In recent years, buffer layer failures of high-voltage corrugated aluminum cables have occurred many times. The typical characteristics are ablative holes, and white powders on the surface of water blocking tape, while the failure mechanism of buffer layer ablation has not been clearly stated. In this paper, a finite element simulation model of 110 kV corrugated aluminum cable with a cross-section of 800 mm² is built, and the influence of volume resistivity and relative permittivity of water blocking tape and air gap distance on the electric field of the buffer layer is studied. The results demonstrate that the maximum electric potential and field intensity of the buffer layer rise with the increase of volume resistivity and decrease of relative permittivity. With the air gap distance between water blocking tape and aluminum sheath decreasing from 0.6 mm to 0.01 mm, the maximum potential of the buffer layer remains constant when the air gap is larger than 0.1 mm, while increases when the air gap is smaller than 0.1 mm. But for the water blocking tape without white powders, the change of air gap distance has little effect on the field intensity.

high-voltage corrugated aluminum cable;water blocking tape;volume resistivity;relative permittivity;air gap distance