Project: Development and application of cable joints with density gradients and adaptable joining force

Due to European conclusions of both the European Parliament and the European Commission the infrastructure of energy distribution has to be re-built because of the growing input from alternative resources, especially from solar power stations (both thermal and direct transformation) and off-shore wind parks. Parallel, the telecommunication systems are in reconstruction with the extension of ulta-fast networks into the less densely populated areas. Any of these actions increase the need of cables and cable joints to break down the high voltages on the production site to the transformation site and to the consumer. This leads to several stages of voltage, startig from high voltage (100 to 400 kV), the networks operating with medium voltage (between 1000 and 100,000 V), the consumers are supllied with low voltages (200 to 400 V), the telecommunication operates at 42 V. For any of these different voltage ranges is a need to connect cable ends by an easy and efficient and low-cost method. _x000D_To this end, a new method of producing such cable joints is proposed based on a new segregating polyurethane system where soft and rigid doCOs segregate with the support of nanoparticles forming a polymer with a density and hardness gradient. The polyurethane system is built up COly on a new combination of a variety of polyetheralcohols and short chain extenders and/or crosslinkers containing a small amount of special nanoparticles such as mixed metal oxides and/or graphene products or oligourea particles in the range of 3 to 120 nm to result in such conditions during polyurethane formation that a very fast segregation of doCOs occurs leading the more rigid parts of the polymer to move to the outer wall of the mould and the softer parts to the inner region. This mixture is reacted in the presence of a catalyst mixture with special prepolymers produced of di- and/or polyisocyanates. The mixtures of both components are chosen in such a way so as to control segregation further by the segregation ability of the ratio of urethane and urea groups in the prepolymer and its reactivity towards the various hydroxyl groups of the A component. Another feature of the project is the development of a new technology and the construction of a new type of moulds to be used. The moulds are to be constructed in a way that they are forming a serial assembly to be filled in a serial production and the temperature controlling unit of each connected to each other by a counter-flow arrangement to use the heat of reaction of the last moulds to heat the first ones._x000D_The technology will be based on polyurethane processing making use of a two-component low or medium pressure machine for short shot times even at larger amounts – the cable joints have a mass in the range of 25 to 2500 g each – as the reaction of the system is expected to be short and proceeds in the range of 10 to 30 s to meet the demand of short demoulding times. The cable joints thus produced in one production step are thoroughly characterized by mechanical, thermo-mechanical, electrical, and environmental tests under various conditions and with field tests to receive feedback for improvement of the system(s) and technology. _x000D_The CO market is the energy distribution and telecommunication. This market is estimated for Europe with some 100 mio cable joints annually, globally it is estimated to be 160 mio pieces. This is expected to grow to 15 and 8 %, resp. _x000D_The consortium is built up of the members _x000D_GT is one of the leading companies of cable connectors worldwide and holds a strong and expanding position in this field. GT offers a complete range of products in this field. _x000D_ELMET is acting more European and has a strong position in the European market with electrical distribution systems in the low and medium voltage area. In Eastern Europe is her expansion field to penetrate into the Eastern European and Middle East countries with its technology. _x000D_B.T. & C. is a specialist provider of power distribution systems in low and medium voltage busbar trunking as well as solutions for electrical connection and sealing. The company is taking market share abroad, Europe, Africa, Russia. There is a need of extension into the medium voltage region so as to expand further in this area._x000D_EUROPUR is one of the major producers of polyurethane elastomers and thermoplastic polyurethanes in Slovakia with extensions into Eastern Europe. _x000D_TH Wildau and University of Kassel have a broad knowledge and experience in materials development and in designing and evaluating parts of energy distribution systems.

Acronym GRADCAB (Reference Number: 6387)
Duration 01/05/2012 - 31/07/2014
Project Topic The project is aimed at a new type of cable joints consisting of a polyurethane system to produce a hardness and density gradient within the polymer showing high hardness at the outer shell with successive decreasing of hardness to the inner surface so that cables are fixed by adjustable pressure.
Project Results
(after finalisation)
The CO result is a completely new construction and type of cable joints and cable distributers and cable stoppers which can be employed on site without the use of any tool or means to increase the temperature. The new types of joints consist of a body made in one shot of a solid shell with a foam inlay of decreasing density with an inner shell of increased density and inner layer with a gel on top, two of such shells are connected by an elastomer hinge to be closed by a new closure mechanism so that cables are placed into the gel layer and the construction accepts the pressure on closure without the need to apply high force or flame. To achieve this, several sub-results were obtained which are_x000D_(1) the development of formulations to result in the materials with distinguished properties applied by machinery in one mould,_x000D_(2) the development and construction of mixing equipment to produce systems based on the formulations with extended shelf life to be processed on two component high pressure machinery _x000D_(3) the construction of moulds suitable to perform the process and to obtain the final products in one shot by using one or two of the two component machines with simultaneous export of the mixed components_x000D_(4) the development of a processing technology to produce the new types of cable joints or branches within the newly constructed moulds by simultaneous filling the moulds at certain temperature ranges suitable for the reaction of the components to result in materials of differing properties from elastic to solid and compact to light weight foam._x000D_The tests of the final cable joints, branches, or stops by mechanical tests showed extraordinary high properties and by electrical tests breakthrough voltages which allow the use not only in the low voltage branches but also in the medium voltage branches, i. e. an extension of the applicability of the cable joints, branches, or stops in other fields of economy than originally planned. Furthermore, the extraordinary properties of the final products exceed those of the aims of the project and are such that the consortium discusses new fields of application of the process and materials developed._x000D_
Network Eurostars
Call Eurostars Cut-Off 6

Project partner

Number Name Role Country
6 GT Elektrotechnische Produkte GmbH Coordinator Germany
6 Universität Kassel, FB Elektrotechnik/Informatik Partner Germany
6 EUROPUR s. r. o. Partner Slovakia
6 Technische Hochschule Wildau - University of Applied Science Partner Germany
6 SC Elmet Energie SRL Partner Romania
6 B. T. & C. Produits Electrotechniques S. A. R. L. Partner France