Power cables

Electricity transfer generates losses in the form of heat. By improving the heat dissipation of power cables, substantial savings can be made. The open structure of CABLOFIL^® maximises ventilation and therefore reduces installation and operational costs.

ASSESSMENT

When an electrical current is running, the copper or aluminium cable cores heat up. The heat given off, known as the Joule effect, is caused by the resistivity of the material (its ability to resist the passage of an electric current). This resistivity increases with temperature. If confined, the heat given off will increase the ambient temperature, thereby increasing both resistivity and resistance. To enable the required current o flow, more power will have to be supplied, with more energy being wasted. The resistance R of a conductor (cable) is proportionnal to the resistivity ρ of the material, based on cross section (S) and length (L). R=ρ x L/S Power P dissipated by the Joule effect: P=R x I², where I is the current's intensity.

SOLUTIONS

- Increase the cross section of cables to reduce resistance. - Ventilate cables to reduce heating. As 90% of it's structure is open, CABLOFIL is the closest solution to running a cable in free air and, in many cases, the standards do not make a distinction between the two. the international standard IEC 60 364 offers practical advice on the cross section of the cables to be used, depending on how they are being installed.

ENERGY SAVING EVALUATIONS

The following tests were conducted at Bureau Veritas - LCIE to compare the affect on cable performance by different cable tray systems. Power cables are fed a steady current. Energy consumption is compared for different configurations. The test results show that consumption differs significantly between open and closed systems. The graph below shows how the choice of system can affect overconsumption of electricity (by as much as 37%)

In spite of the electrical protection equipment of the network, energy transfer will always present risks to people and property.
CABLOFIL® is able to manage these risks with its high performance cable supports.

SHORT CIRCUITS

A short circuit occurs when a connection is accidentally established between two points in an electric circuit at different voltages. It presents a risk to both property and people. Depending on where it occurs, very large currents may be generated, which will often result in a fire. The main causes of short circuits are as follows: - Damage to insulating materials as a result of wear and tear or mechanical impact - Broken conductors - Conducting elements falling onto or otherwise coming into contact with the circuit

SHORT CIRCUITS TESTS

Test were performed at a recognized independent laboratory (DAMSTRA) and in accordance to standard EN 50 368 (2003) in order to validate CABLOFIL's mechanical resistance to the stress generated by a short circuit. An initial short circuit is generated during the tests, creating mutual electromagnetic repulsion between the power cables. The cable tray is then subjected to substantial mechanical stress for a very short time (approx. one second). The process is repeated in order to show that CABLOFIL is structurally intact and able to cope with another short circuit. As a final measure, additional tests are performed in a damp environment to check whether the cables are fully intact.
The various tests are run with 3 successive levels of short-circuit current: - 70 kA, equivalent to a repulsive force of 1300 daN - 100 kA, equivalent to a repulsive force of 2700 daN - 130 kA, equivalent to a repulsive force of 4500 daN

Material used: 3 m of CF105/450 coupling 1/5th of the way along the span, 5 fast couplers and a support span of 1.5 metres.
System configuration: 3 single conductors power cables, 38 mm in diameter, are attached every 600 mm using cleats.

Before test		During		After test

CONCLUSION

The tests reveal that the wire cable tray shows no permanent deformation, its mesh structure is able to absorb the physical stress generated by a significant short-circuit current. The cables remain intact in their original positions and network availability is maintained. >> Go to the Video