Paper insulated lead cables (PILC) have been in use for more than 100 years in MV Applications between 6.6KV up to 36KV and even in HV systems. PILC has been preferred over the years due its high dielectric strength, low dissipation factor, relatively low dielectric loss, low sensitivity to DC testing and proven reliability. PILC has become less popular over the years as it is being replaced by cross linked polyethylene (XLPE) due to factors impacting its cost-effective use. Many cable manufactures around the world have discontinued PILC due to the related reduction in demand.
XLPE as an insulating medium have a lower dielectric constant, lower dielectric loss and high dielectric strength and operates at higher temperatures allowing the cable to be more efficient, carrying much more current than the same size cable of paper insulation impregnated cable. XLPE is generally much more preferred by customers for factors to do with ease of use, efficiency, less accessories complexity and others.
Below are some of the factors why XLPE is much more preferred than PILC for MV cables as insulation;
- XLPE has a higher current rating compared to the same size PILC cable due to the fact that XLPE has a higher operating temperature.
- The installation, maintenance and repair processes are more complex, intensive, timeous and high on cost for PILC cables compared to XLPE, making XLPE a better option for the customers.
- The accessories such as jointing and termination kits are not easy to find as many factories worldwide have discontinued paper cable production in their factories.
- Concerning skills shortage for splicing, jointing and termination of Paper insulated cables is also driving customers to move to XLPE cable. Many PILC cable failures due to suspected poor workmanship related to skills gap.
- Although PILC has been better at providing radial water blocking properties with the lead sheath which is completely impermeable, XLPE is also available in cost effective water blocking formats for both longitudinal and radial water blocking upon request (by customer) from the top cable manufacturers such Aberdare Cables in South Africa.
- XLPE Cables are more flexible compared to PILC Cables which are more rigid especially for larger sizes. This ensures that XPLE can be used where shorter bending radius is required.
- Paper insulated Lead Cable is oil impregnated with mineral oil or PIB and a lead sheath (heavy metal) which increases the risk of environmental contamination, XLPE is favoured in many of the situation where an environmental analysis is considered as a key consideration for design decision.
Aberdare Cables Pty Ltd in South Africa offers XLPE cables up to 132KV for customers across Africa and around the Globe. For Voltages higher than 132KV XLPE cables can be provided by Aberdare cables through the parent company Hengtong Group in China.
