Cable faults

Basic conditions, causes, and types

Cable routes are influenced by a variety of ambient parameters. A cable route can consist of multiple diverse cable parts of diverse construction types. Depending on the voltage level, 
the required load capacity, and available accessory and installation technology, cables with plastic insulation or mass-impregnated paper insulation are used. 

 

Cable damage can be due to various causes. The most common sources of faults include end of service life and external influences as well as improper assembly. When these types of cable faults occur, the defective spot needs to be detected as quickly as possible and the fault rectified in order to minimise the duration of the failure.

 

It is helpful if the cable fault location equipment can be used for all voltage levels right across the network. In practice, cable faults must be located on all voltage levels – from low voltage through medium voltage to high voltage. 

 

All from a single source

The BAUR device portfolio meets this requirement and satisfies all needs concerning cable fault location, testing, and diagnostics.

Common types of cable faults

Short-circuit

 

Damaged insulation leads to a low-resistance connection of two or more conductors at the fault location.

Short-circuit to earth

 

Earth faults or short-circuits to earth are low-resistive connections to the earth potential. The double earth fault is another type of fault; this fault shows two earth faults on different phases with separated bases.

Cable sheath faults

 

Damage to the outer cable sheath does not always lead directly to faults. However, it can cause long-term cable faults, among other things, as a result of moisture penetration and insulation damage.

Intermittent faults

 

Frequently, faults do not occur constantly, but rather occasionally depending on the load on the cable. One reason for this can be drying out of oil-isolated cables with a low load. Another is partial discharge through ageing or electrical trees in cables.

Cable breaks

 

Mechanical damage and ground movements can lead to breakage of individual or multiple conductors.

Further topics relating to cable fault location: