Very Low Frequency (VLF) 0.1 Hz testing is used on XLPE cables as an alternative to DC testing to prevent polarisation and premature damage to the insulation. It is designed to identify weak spots due to electrical trees in the insulation. Cosine rectangular 0.1 Hz systems have been developed to meet international standards such as IEC HD 620/621 and IEEE 400. The benefit of the cosine rectangular waveform is that you can test longer cables to the standards of 0.1 Hz. Many of our VLF test systems also feature dc and pulsed dc outputs to enable sheath testing, and sheath fault pin-pointing using the ESG NT.
The fundamental objective of any cable fault location system is to provide quick, effective, accurate and safe fault location, resulting in reduced system outages and “Customer Minutes Lost”. Megger’s fault location systems help you quickly find the location of the underground fault.
These are used in conjunction with a surge generator or sheath fault locator pulsed energy source to find the exact location of a fault.