HPTE Extruded Cables Polarity Reversals Performance in LCC HVDC Systems

The first part of the paper introduces the main operational differences, from a cable system perspective, between line commutated converter (LCC) and voltage source converter (VSC). As LCCs perform power reversal by inverting the DC voltage polarity, the general theory for cable insulation electrical stress calculation in this condition and the main reasons why it is a severe stress for extruded cables are reminded. In the second part, the development of the innovative High-Performance Thermoplastic Elastomer (HPTE) extruded material is introduced. This material presents superior electrical and thermal characteristics which will allow the use of extruded cables inside LCC systems. Several polarity reversal tests have been successfully carried out at different voltage levels up to 525kV and are presented in this paper for the first time. The test results are applied to a case study, where an HPTE cable is designed for an LCC application up to 2 GW.