Electrical stress reduction electrode for screened power cable - has plastics sections of different nonlinear resistivity load with active particles having nonlinear electrical resistances

摘要

The core of the power cable is surrounded by insulating sheath with a conductive screen. The electrode consists of successive sections of different electrical resistance, typically increasing towards the high-voltage part of the cable joints. The sections are made from one or more mixtures of plastic material with particles of nonlinearly resistive products (e.g. SiC) at concns. which may vary for the same grain size, or may be comparable for different grain sizes. The device is suitable for working voltages as high as 63kv at which the max. potential gradient at the electrode-insulation interface is less tha 4kV/mm. For higher voltages up to 90kV an underlying insulating layer of comparable thickness may be provided within the electrode. Perfectly linear distribution of voltage is attainable along the exposed parts of the insulation.