Why We Perform A VLF Test?

ATE has provided a very good reasons on this article why high voltage withstand tests on cables are necessary.

Past practices involved HVDC Hi-pot or DC leakage current methods. They not only provide insufficient diagnostic precision instead these tests can lead to development of water trees in the cable insulation.

A Filipino Engineer, Registered Professional Engineer of Queensland (RPEQ) - Australia and Professional Electrical Engineer (PEE) - Philippines with extensive experience in concept select, front-end engineering, HV & LV detail design, construction and commissioning of Hazardous and Non-Hazardous Area electrical installations in water and waste water pipeline and pumping facilities, offshore platforms, hydrocarbon process plants and pipelines including related facilities. Hazardous area classification and design certification (UEENEEM015B, UEENEEM016B, UEENEEM017B).