Very Low Frequency Testing

It is now recognised throughout the power industry that DC testing of solid dielectric cables (XLPE & EPR) has limited ability to expose cable defects and that the DC test can precipitate damage to the insulation causing premature failure of the cable in the future.

Many industries and utilities have now turned to VLF testing to avoid the risk of ‘negative space charging’ leading to electrical trees, partial discharge and ultimately premature cable failure.

The IEEE now recommend the use of VLF testing and discourage the use of DC testing.

VLF is an effective way of AC testing cables and plant without exposing the insulation to the consequences of harmful DC testing giving a pass or fail result.

We can offer VLF testing up to 70kV enabling us to carry out the effective testing of power cables up to 33,000V with a maximum cable length of up to 20km