Study on the capacity of sheath-protecting surge arrester at a 230 kV cable end

For relatively long cable system, the cable is subdivided into minor and major sections. The sheaths of each minor section are transposed or cross-bonded. Meanwhile the sheaths at both ends of each major section can be grounded, or only the sheaths at the sending end are grounded and at the other end are left open. When short-circuit faults occur close to the ungrounded end, the overvoltage appears between the sheaths and local ground. The arresters which are connected to the ungrounded sheaths suffer more from the overvoltage stress compared to those connected to cross-bonded sheaths. Hence, the absorbed energy capacity of these arresters is of interest to be studied. This paper investigates the influence of some parameters (such as grounding resistance, lead inductance, ratio of source impedance, and rated voltage of arrester) on the arrester capacity. The choice of the absorbed energy capacity (KJ/kV) of arrester is also discussed. The case of a single line to ground fault on a 230 kV cable system is considered. The simulation is carried out using PSCAD/EMTDC.