For more than 20 years, Cross linked polyethylene cables (XLPE) Extra High Voltage (EHV) Alternating Current (AC) cables have a proven track record. From 1996 to 2015 alone, globally some 4,691 km cables have been installed, of which:
- 1,940 km of 220 – 235 kV
- 1,073 km of 245 – 345 kV
- 1,678 km of 380 – 500 kV
Projects include installations in Abu Dhabi, Argentina, Austria, Bahrain, China, Denmark, France, Germany, India, Ireland, Italy, Japan, Mexico, The Netherlands, Portugal, Qatar, Russia, Saudi Arabia, Singapore, Spain, South Korea, Sweden, Switzerland, Taiwan, Tunisia, Turkey, UK, Ukraine, United Arab Emirates and the USA. EHV AC cables serve as connections to power plants and substations (both onshore and offshore), transmission feeders circuits into densely populated urban environments, undergrounding overhead lines in areas of outstanding beauty as well as undergrounding existing overhead lines such that the land becomes available for commercial or residential development. EHV XLPE cables are recognised as a technology that performs well based on the requirements established by the International Standard IEC 62067.
When deployed in the Partial Undergrounding Concept complementing overhead lines, 380 kV AC cables are:
- Reliable: Thoroughly tested, increasingly used, proven technology. Once in the ground, cables are well protected against any external severe weather influences.
- Sustainable: Limited environmental impact during installation and operation, no restriction in agricultural use of the trenches with reinstatement of the same topsoil.
- Affordable: While investment costs for the undergrounded section are some 3 -10 times the cost for that of covering the same stretch by overhead technology, costs for the entire line will only increase by smaller factor. At the same time, the line may be built more rapidly, with speedier route approvals, a limited visual impact and a lesser deprivation of property values in the vicinity of the cable route.
- Publicly Acceptable: Any transmission line has an environmental impact, yet experience shows that public acceptance for partially undergrounded lines is higher than for overhead lines.
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