Resonant overvoltages in HV cable testing

An analysis of transient overvoltages that develop during impulse tests on HV cables indicates that a transient overvoltage can be initiated in the test cable as a result of a resonance phenomenon between the capacitance and inductance of the cable and the connecting leads. The magnitude of this overvoltage was found to vary along the length of the test cable, with maximums occurring at the open end when the cable is energized from the other end, and at the centre when the cable is energized from both ends. The theoretical results are well supported by direct measurements on a 15-kV PE cable sample subjected to impulse voltages. Finally, a simple means of avoiding resonant overvoltages is presented which could be useful in future testing of HV cables.