Condition Assessment of HVDC Cables during their Lifecycle

Abstract

Recent market developments towards power generation in remote renewable power plants such as concentrated solar power plants in deserts or large off-shore wind parks, raise an interest for long distance power transmission via extruded HVDC cables. HVDC cables require quality assurance during the complete product lifecycle, mainly: a) R&D activities for design verification and - validation b) routine tests in the factory for confirmation of proper manufacturing c) acceptance test after erection and commissioning to exclude defects caused during transport and installation d) ageing monitoring and quick fault detection and location detection during service life. Considering increasing voltage levels, increasing cable lengths and ground or even offshore installation, the dielectric testing of extruded HVDC cables in the factory and on site remains challenging. The long-term validation of insulation coordination requires high voltages for quality assurance tests which represent typical expectable stresses during service. Typical examples are wave shape, partial discharge behavior and dielectric field stress in the insulation medium. Hence, different technical solutions are available to generate these required high voltages for testing of HVDC cables. This paper discusses essential technical and commercial aspects of HVDC cable quality assurance and presents suitable methods for HVDC cable testing.