XLPE stands for “Cross-Linked Polyethylene.” This insulating material has become almost universally established in medium- and high-voltage cables. XLPE is temperature-resistant, ageing-stable, and enables compact, high-performance cable designs. XLPE cables are now standard in power supply and are progressively replacing older paper-oil cables throughout the medium- and high-voltage range.
What advantages does XLPE insulation offer?
Through chemical cross-linking, the polymer chains lose their ability to melt – the material becomes highly temperature-resistant and significantly more mechanically resilient. XLPE cables may be operated continuously at a conductor temperature of 90 °C, and briefly even up to 250 °C during a short circuit. This makes them excellently suited to high-performance applications.
Key Characteristics at a Glance
- Continuous operation up to 90 °C conductor temperature
- Short-circuit temperature up to 250 °C
- High electrical strength and low dissipation factor
- Good resistance to moisture and chemicals
- Available from low voltage up to extra-high voltage (up to 550 kV)
- Economically superior to older paper-oil cables in almost all applications
- Maintenance-free design without an oil filling
- Compact design with reduced wall thicknesses
Frequently Asked Questions
How does XLPE differ from conventional PE?
While thermoplastic PE softens and melts at higher temperatures, XLPE is chemically cross-linked and remains dimensionally stable. This allows XLPE to be operated at higher temperatures, enabling greater current transmission capacity for the same cross-section.
How is an XLPE cable connected?
Via appropriate cable terminations selected to match the respective voltage level and design. Proper field control and, where necessary, shielding are important to avoid partial discharges and ensure service life.
How long do XLPE cables last?
With proper design and installation, XLPE cables achieve service lives of 40 years or more. Prerequisites are careful termination and joint installation, avoidance of mechanical damage during laying, and protection against excessive heating during operation.
What methods are used to diagnose XLPE cables?
Common methods include partial discharge measurement (offline and online), dissipation factor measurement (tan δ), and VLF (Very Low Frequency) testing. These methods reveal ageing, damage, or water ingress at an early stage and enable predictive maintenance as well as targeted repairs.
Do you have questions about cables, terminations, and connection technology for XLPE systems? We provide comprehensive advice – talk to our team.