Cable Fault Location

HV/LV cable faults are inevitable, although quite rare, and are caused mainly by moisture ingress into damaged small third-party cables or cable joints. They can cause a protection device, such as a circuit breaker or switch-fuse, to operate with a consequent loss of supply.

Once identified, the fault needs to be located and repaired as fast as possible. This is achieved using the dedicated HV3 fault finding test van. Faults are generally either earth faults or open circuit faults, and can be permanent or intermittent.

Permanent faults are located using a combination of pulse echo, impulse current and capacitor discharge devices to provide a precise location. Excavation and jointing, Testing is then carried out to restore the network.

Intermittent faults can be made permanent by ‘fault Conditioning equipment’ that uses high current, but low voltage, to accelerate the degradation. The fault can then be located as normal.

The supply of electrical energy is getting more and more important within our society, it is necessary to make sure that power supply system works without any problems. Cables are used for the distribution of the electricity, and today cables are highly developed but there are sometimes malfunctions in the cable system. To keep the down time as small as possible, trained staff and efficient equipment is needed to locate the fault.

Our dedicated HV/LV Fault finding test vans carry a variety of sophisticated equipment for the fastest possible location of faults in underground/subsea cables. We use cable fault location instruments and equipment that are applicable to all types of cables ranging from 415V to 400 kV and all types of cable faults such as:

• Earth faults
• Phase to Phase
• Cable Damage
• Resistive faults
• Intermittent faults
• Sheath faults
• Partial discharges