Dielectric Tests on Cable Testing Circuits of Medium Voltage Switchgear

The dielectric test of power cable is a most important inspection operation in its whole life cycle. Generally, dielectric tests on cable testing circuit are carried out through available electric connection points in medium voltage (MV) switchgear. in consideration of that some parts and switch fracture of the switchgear also bear the effect of cable test voltage stress during cable testing, new requirements for the insulation level of the above components to withstand various types of combined voltage are put forwarded. This paper analyze the test conditions of cables in switchgear situation, give the cable dielectric test circuit in line with IEC62271- 200:2011, discuss the rated cable test voltage, summarize and give the recommended values according to relevant standards or specifications. Finally, combined with engineering practice, the advantages, disadvantages and application of DC withstand voltage, AC withstand voltage, ultra-low frequency and oscillating pulse voltage methods are compared and analyzed.