加速劣化試験を実施した6.6 kV CVケーブルの水トリー劣化調査に基づく水トリーのモデル化と過渡電界解析による直流漏れ電流・交流重畳電流の算出と交流絶縁破壊電圧の推定

抄録

The authors were able to generate a penetrated water tree in an extruded three layer (E-E type) 6.6 kV XLPE cable subjected to an accelerated water-treeing test, and measured DC leakage and AC superposition currents of the cable. In this study, the penetrated water tree was modeled and DC leakage and AC superposition currents were calculated by using transient electric field analysis, and the calculated currents and measured ones were compared. In addition, the conductivity of water trees was selected so that the calculated AC superposition current was equivalent to the average value of the measured values, and DC leakage and AC superposition currents were calculated for a non-bridged water tree obtained after the accelerated water-treeing test. Furthermore, the shapes of water trees were assumed as spheroidal ones, and the DC leakage current, AC superposition current and AC breakdown voltage were analyzed when the length and width of the water tree changed.