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Testing high voltage power cable systems

Testing after installation help identify defects due to improper installation, while diagnostic tests during lifetime prevents failures due to ageing and degradation. 

Neka carry out the testing and interpret the results providing insight into the present health and possibly the remaining life of the cable. From this we can offer recommendations for maintenance, repair, replacement or operation based on the observed quality of the cable.


Advanced cable diagnosis with Damped AC reveals and locates weaknesses in terminations, joints and cable, as well as the general insulation aging. The system is tested with an overvoltage so that weaknesses that are triggered by earth faults are also revealed. Cable systems from 6.3 to 250 kV with a length of up to 30 km can be tested.


Partial discharges (PD)measurements without service interruption

Partial discharge is considered as the largest contributor to insulation degradation. PD measurements can be performed on most types of systems from 6 to 420 kV without the need for downtime. The equipment can also be temporarily mounted for monitoring over time. Periodic PD measurements help to avoid accidents


Line Impedance Measurement

Measure line impedances and k-factors on overhead lines and power cables.


Ground impedances can also be determined on large systems, as well as touch and step voltages


Shorter cables (< 30 meters) can be tested at power frequency. Mainly used on duplex cables in substation or on cable/joint/termination samples as a part of FAT or RD projects. We perform power frequency withstand testing up to 120 kV. 


The test can be combined with PD measurements.


Hipot insulation test with VLF Tan Delta is the best method for detecting watertreeing in pex insulation, as well as moisture in cables / joints.


Cable diagnosis with
Line Resonance Analysis (LIRA)

The diagnosis detects and locates changes in the electrical parameters in the cable. Used on all types of cables up to 250 km 


The cable system is exposed to an overvoltage with the intention of provoking a controlled breakthrough in weaknesses in the cable, joints and terminations.

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