The insulation of HVDC extruded cable system joints. Part 2: Proposal of a new AC voltage PD measurement protocol for quality control during routine tests

Abstract

The review of materials, design and testing of joints for HVDC extruded cable systems provided in previous Part 1 paved the way to this Part 2 position paper by the DEIS HVDC Cable Systems Technical Committee, whose aim is to remedy the scarcity of existing standardized tests on joints. After a sound analysis, here routine tests are identified as the first practical target for the onset of new testing procedures, AC-PD measurements as the readily-available measurement from manufacturers' experience for quality control of joints during routine tests and VHF/UHF wireless sensors as the best tool for such measurements in the noisy environment of factories. Thereby, a novel protocol for PD measurement using AC voltages and VHF/UHF electromagnetic sensors, for quality control during routine tests on HVDC extruded joints, is proposed.

Issues and Challenges for HVDC Extruded Cable Systems

“…A main challenge for the fairly-innovative and fast-developing HVDC extruded cable technology is the development of durable and reliable accessories, i.e., joints and terminations, as accessories are the weak links of HV cable systems [5,10,[17][18][19]. Testing and service experience show that especially joints are the most critical components for cable system reliability, as the number of joints can be huge, particularly in long underground HVDC links like the German Corridors [2].…”

“…The issues relevant to cables and accessories of HVDC extruded cable systems require new and more effective testing techniques of such components. These techniques include space charge and partial discharge measurements, and were broadly studied in the literature (see [18,19,146] for a review). From these studies the IEEE DEIS TC "HVDC Cable Systems" has issued two new standards that provide guidelines for testing HVDC cable system components with these new techniques.…”