IEEE Recommended Practice for Space Charge Measurements on High-Voltage Direct-Current Extruded Cables for Rated Voltages up to 550 kV

Abstract

The aim of this recommended practice is establishing a protocol for the measurement of space charges in high-voltage direct-current (HVDC) extruded cables having rated voltage upto 550 kV. Such measurements are prescribed to be carried out at the beginning and at the end of load cycle qualification tests (either the long-duration voltage test of prequalification tests or the load cycle test of type tests). The various steps of the protocol for the measurement of space charges in such cables are carefully described. Details are given about the procedure for applying and switching off the voltage, the preparation and conditioning of specimens, the measurement times during poling and depolarization, and the calculations for checking electric field stabilization. The ultimate goal of this recommended practice is not verifying the compliance with any maximum acceptable limit of either space charge or electric field, but rather assessing the variation of the electric field profile in the cable insulation wall during load cycle qualification tests.