Executive Summary : | The HVDC power cable technology enables the transmission of power generated through offshore wind farms and other renewable energy via cable links to the grid. Cable is one of the important components which needs to be designed and monitored for continuous power supply. International research community (CIGRE WG8 IEC112, of which the PI is a member) is working on measuring space charge distribution in power cables that makes it possible to understand the aging phenomenon and estimation of the design life. The aim of this project is to investigate the long term electrical aging phenomenon of HVDC power cables insulation. We propose to evaluate the space charge accumulation with AGEING and distribution under continuous HVDC and polarity reversal step stress until breakdown. Also, we aim to develop a prototype of a single setup which is capable of measuring space charge and leakage current simultaneously, even at higher temperatures. The accumulation of space charge within the insulation bulk is one of the main factors responsible for failure of HVDC cables. Electrical aging brings about dynamic changes in the space charge distribution.Owing to the lack of standardized methods, the design life of HVDC cable insulation has been based on AC step-stress breakdown tests until now. However, such an estimate may not always be accurate because of the difference in the nature of a dielectric (capacitive/resistive) under AC and DC voltages. Therefore, we propose to estimate the life of cable insulation based on DC step-stress tests itself. |