Silicones against Blackouts - Wacker Chemie AG


Silicones against Blackouts

Application tests with 1,200-kilovolt Deccan insulators.

200 GW of Generator Capacity

A comparison of figures clearly shows that the provision of electrical energy is by far not enough: some 200 gigawatts of electrical-generator capacity are currently installed in India. Every Indian can thus use 170 watts, on average. By comparison, every German can draw on seven times that amount. Furthermore, 300 million Indians have no access to electrical energy at all. In rural areas, electricity is pure luxury and sometimes even tapped illegally. This unbalances the grids further and makes them more susceptible to blackouts.

The Indian government is following ambitious plans to expand its energy grid in order to meet rising demand. “An additional 100,000 megawatts of power will be required over the coming five to seven years,” explains Vikas Jalan, joint managing director at Deccan Enterprises. The company, which has a rubber-processing tradition that spans over 40 years, has been developing and producing silicone-elastomer composite insulators for power transmission for several years and is a market leader in India.

Since electricity is mainly produced in coastal regions and the northeast and east of the country, but energy is needed nationwide, the subcontinent needs more than just new power plants. “Power transmission also needs to be expanded accordingly,” says Deccan manager Jalan. New extra-high-voltage lines with voltages of 765 to 1,200 kV are in particular demand. They provide the only low-loss means of transporting the required amounts of electricity over long distances.

Insulators are a key element of energy transmission and distribution. They can be found wherever electrical conductors must be affixed, held or guided. Silicone composite insulators are currently in particular demand in India. Put simply, they consist of an electrically insulating glass-fiber reinforced rod in a weather-resistant silicone-elastomer housing. “Compared to conventional porcelain insulators, the electric silicone-elastomer composite components are significantly easier and faster to manufacture and more cost-efficient over the long term,” explains Lambrecht. This is because the insulating housing is not fired like ceramic components, which is complex and time-consuming, but applied via injection molding. With this method, production not only yields high-precision molded parts, it is also rapid and the required high quantities are possible.

“An additional 100,000 megawatts of power will be required over the coming five to seven years”

Vikas Jalan, joint managing director at Deccan Enterprises

The Product

POWERSIL®

stands for special WACKER silicones for applications in the transmission and distribution industry. POWERSIL® rubber grades, with their long-lasting hydrophobic properties, tracking and arc resistance, and good UV resistance, offer special advantages for use under severe climatic conditions, for example in coastal areas or desert climates.

At 2,000 Bar into the Mold

“Injection-molding machines press the silicone material into steel molds at a pressure of up to 2,000 bar,” explains Harald Schmid, sales manager at Klöckner DESMA Elastomertechnik GmbH. “The design and manufacture of these molds require extensive production expertise, in particular.” The German injection-molding machine manufacturer Klöckner DESMA is now the market leader in India, too. The Indian sites have been designing and making the casting molds, which weigh several tons, for the past four years. They consist of up to 400 precision parts, must be made very accurately and must be able to withstand high injection pressures. This three-dimensional template gives the insulators their typical lamella-like sheds. “They protect the component against electrical discharges that can be caused by adherent dirt,” explains WACKER expert Lambrecht, a high-voltage engineer by training. In addition, the hydrophobic, i.e. water-repellent, silicone surface reduces the risk of flashover, “since no electrically conductive film of water can form, which could easily happen with porcelain. Rain drops simply roll off,” continues Lambrecht. So, adherent dirt does not become electrically active.