High Voltage (HV) and Medium Voltage (MV) Cable Testing and Diagnostics – onsite hv ag

onsite hv ag offers a wide range of products in the categories of Cable Testing and Diagnostics, Coil and Winding Insulation Diagnostics, and Transformer Diagnostics. The onsite hv group consists of several companies located in Switzerland: onsite hv solutions ag in Luzern, is an international organization of independent companies with a team of highly qualified specialists, providing knowledge of modern on-site solutions to distribution and transmission utilities. onsite hv international ag, is a distributor for innovative test and diagnostic tools to the Electrical Energy Industry and is a reliable partner for utilities, power suppliers and grid operators as well as producers of equipment for electrical grids.

High Voltage Testing Products and Innovative Power Utility Services - onsite hv ag

After laying, testing and diagnosis of newly installed, repaired or service-aged (E)HV cable systems is key to the successful operation of transmission networks. EMT exclusively offer the UK & Ireland high-end testing and diagnostic tools from onsite hv including state of the art medium voltage (MV) cable testing and diagnostics and high voltage (HV) transmission cable testing and diagnostic tools specialising in the fields of:

VLF (very low frequency) Cable Testing

Tan Delta Measurement

Partial Discharge Measurement 

PD Mapping

OWTS HV Technique

DAC voltage test and diagnostic measurements by Partial Discharges and Dissipation Factor (Tan Delta) provide reliable detection of poor installation; failures due to inappropriate laying; failures in accessories; and deterioration in cable insulation due to ageing. It allows much more than a simple “go or no-go” decision. DAC testing is an advanced maintenance tool which supports asset management and grid operation. Products offered in this field include: DAC MV 30 / 30kV - DAC MV technology for on-site testing (up to 21 kVrms) with diagnosis by partial discharges and dissipation factor estimation for all types of distribution power cables; and DAC HV400 / 400kV - DAC HV technology for on-site testing (up to 283 kVrms) with diagnosis by partial discharges and dissipation factor estimation for all types of transmission power cables.

The PD Measurement gives users the certainty to identify PD inceptions during test voltage application. As a result, it allows turn-off of the test if PD appears, and avoids a breakdown during the test if not appropriate (cable under specific surveillance will be exchanged or repaired). Localisation and identification of PD patterns (joints) is also facilitated.

The Dissipation Factor (Tan Delta) estimation is based on the determination of the damping factor of the DAC voltage itself. This measurement gives a reliable indication of the integral deterioration of the cable insulation. Service-aged, oil-impregnated, transmission power cables of more than 40 years old can be differentiated into groups. This method facilitates PD mapping, providing an assessment on the health of cables in consideration of investment for exchange programs, supporting decisions on which cables must be exchanged first and on the best available basis.