The quality of electricity transmission and distribution strongly depends on the behavior of insulating systems. The presence of faults in the high voltage cable, generated during its manufacture or installation, can cause network perturbation ranging from simple partial discharge to the power line decommissioning by total electric discharge. The occurrence of gaseous cavities in the insulation of high voltage cable is the origin of partial discharges because of the electric stress elevation. The determination of this electric field is usually calculated by numerical solving the Laplace equation. The originality of this paper is to establish an analytical model based on the capacitive equivalent circuit of partial discharges who allows estimating the conditions of initiation of these partial discharges using Paschen criterion. The proposed model facilitates the calculation of the threshold voltage of partial discharge and reduces the computation time required by numerical methods. This inception voltage depends on the size of the cavity, its position, conductor radius, thickness of inner semi-conducting layer, type of insulation and its thickness.

电力传输和分配的质量在很大程度上取决于绝缘系统的行为。高压电缆在制造或安装过程中出现的故障会导致网络扰动，范围从简单的局部放电到电力线因完全放电而退役。由于电应力升高，高压电缆绝缘层中气穴的出现是局部放电的起源。该电场的确定通常通过数值求解拉普拉斯方程来计算。本文的独创性是建立基于局部放电电容等效电路的分析模型，该模型允许使用帕邢准则来估计这些局部放电的引发条件。所提出的模型有利于局部放电阈值电压的计算，并减少了数值方法所需的计算时间。该起始电压取决于腔体的大小、位置、导体半径、内部半导体层的厚度、绝缘类型及其厚度。