The company professionals came to the conclusion that for their purposes, terminations and joints with integrated geometric stress control are technically an excellent solution. Since then, E.ON and many of its contractors have trusted Ensto’s cold shrink technology.
E.ON Sweden’s Technical Specialist Peter Ipsen tells, that Ensto is an essential part of the electricity distribution network in Sweden. “We require that our contractors use cold shrink with geometric stress control and follow the technical specification for the medium voltage cable accessories. In addition, the cable installers must be educated within cold shrink technology and that is something Ensto offers with their Ensto Pro training program.” Ipsen continues that E.ON demands that the installers have a cold shrink installation certification.
Why Geometric Stress Control?
Kenneth Väkeväinen, Head of Product Management, Underground Networks at Ensto explains why geometric stress control is very good technology for cold shrink cable accessories: “Geometric stress control means that the insulating and conducting materials are combined in cold shrink joints and terminations so that we can create a geometric shape to control the electrical stress on various insulation layers.”
According to Väkeväinen, the geometric stress control with the stress cone fits much better in a network, for example in renewable power generation, where a high amount of power electronics is used. When the use of power electronics constantly increases, and the quality of electricity is getting worse along with point load, the stress control elements in traditional cable accessories will start to generate more losses and therefore also more heat. This, in turn, can shorten the lifetime of the cable or the accessory. The quality of electricity does not affect the geometric stress control components, so the accessories with geometric stress control will perform better as they do not suffer from this additional heating. Hence, geometric stress control is The Stress Control Technology for the future.
Technically Superior Silicone
E.ON and Ipsen have years of experience in Ensto’s cold shrink products, and the materials used in them. Väkeväinen outlines: “Let us take air insulated secondary outdoor substations as an example. A bit surprisingly they are more challenging as cable installation venues than the open-air installations: the humidity is the same or even higher but as the rainwater does not wash the products, they get dirty and suffer from humidity.”
"The cable preparation procedure is the same with both heat and cold shrink technologies but after that, cold shrink is faster and safer to install."
Ensto uses silicone in their cold shrink joint and termination bodies, as it is an excellent insulating material. It is hydrophobic and does not suffer from surface discharge on installed terminations in the substation. Thanks to Väkeväinen’s master’s thesis and extensive amount of research data from secondary substations on the field Ensto has a comprehensive overall understanding on the issue. As the cold shrink products are used all over the world, all the customers can benefit from the company’s knowledge.
Quick Installation and Even End-Result
In cold shrink, the geometric stress control components are already pre-installed into the termination and joint bodies in the factory, which means fewer installation steps on the field and hence, time saving for the installer. Pulling out the spiral is fast and there is no need to wait for any cooling down of the tubes before proceeding. For the same reason, the possibility of making human mistakes is minimal. As the number of underground cable installations is growing, there is a lot of work to be done. Then, the importance of flawlessness is increasing as it saves both times, costs, and safety.
Ipsen recognizes the advantages of the cold shrink technology: “E.ON was the first company in Sweden to take cold shrink joints and terminations in use. Truly, the cable preparation procedure is the same with both heat and cold shrink technologies but after that, cold shrink is faster and safer to install.”
Honesty and Open Communication
E.ON and Ensto have cooperated for 18 years, and Ipsen tells, that he appreciates the honesty and openness of the partnership. “If there is a problem, I just talk to Ensto representatives and then we find the solutions together. We have known each other for a long time, and the cooperation is good when the communication is open and on time, and the supplier has resources to support us. Ensto is one of the best suppliers on the market.” According to Ipsen Ensto is well-known in Sweden and many of E.ON’s contractors are using Ensto’s products and solutions.
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E.ON in Brief
E.ON Sweden is part of the international energy group E.ON SE. Within the group, around 70,000 people work in 17 countries. The business mainly consists of two business areas: smart distribution networks and innovative energy solutions for customers.
