Cable-Tech 2024, held on June 13th and 14th in Bangalore, became a focal point for groundbreaking advancements in high-voltage direct current (HVDC) technology. The event showcased significant innovations in the field, with KEMA Labs presenting crucial findings on the resilience of HVDC cable systems to transient overvoltages (TOV).

Transient overvoltages, which can occur during faults or switching events in the DC grid, represent a formidable challenge to the reliability and safety of HVDC transmission networks. Addressing these challenges, KEMA Labs performed a comprehensive assessment on a 525 kV DC cable system, encompassing its outdoor terminations, joints, and the DC cable itself. This assessment was commissioned by a Transmission Service Operator (TSO).

The study employed advanced methodologies to generate various TOV waveforms, such as zero-crossing damped TOV, very slow-front TOV, and fast-front TOV. Each waveform, characterised by distinct peak levels and timings, rigorously tested the system’s limits. KEMA Labs’ research demonstrated that the 525 kV DC cable system is exceptionally resilient to TOV stresses, confirming its reliability under extreme conditions and showing no signs of failure or degradation. Numerical simulations further validated these findings, underscoring the reliability and accuracy of the test methods used.

KEMA Labs’ work exemplifies the forefront of innovation in TOV testing for HVDC cable systems, an area that currently lacks standardised protocols. In addition to presenting their findings, KEMA Labs proposed recommendations for future standardisation of TOV testing, addressing critical aspects and limitations identified in their research.

The presentation at Cable-Tech 2024 emphasised the transformative impact of these innovations on the HVDC technology landscape. Industry experts recognised the critical importance of tests like those conducted by KEMA Labs in ensuring the resilience and reliability of next-generation high-voltage DC transmission networks. The approach received widespread interest from attendees, who expressed a keen interest in integrating these insights into future industry standards.

Image source: Courtesy of KEMA Labs, a CESI division

Read more about KEMA Labs, a CESI division here