Silicones against Blackouts
1,200-kilovolt Deccan insulators in a power grid.
Silicones from Kolkata
In 1998, WACKER and its Indian partner Metroark founded the joint venture Wacker Metroark Chemicals Pvt. for the production and sales of silicones. For some time now, the company has been producing POWERSIL® silicones for electrical components near Kolkata. WACKER expert Lambrecht has been involved from the start, from when the chemical company began expanding to India. Cooperation with Deccan goes back almost as far.
“We had to design very long, new silicone composite insulators for the 1,200-kilovolt test station of energy provider Power Grid Corporation of India Limited,” explains Deccan manager Vikas Jalan. This is because the insulators’ length depends directly on the transmission voltage – almost one meter per 100 kilovolt. Deccan carried out various model calculations and simulations to optimally adjust the electrical and mechanical parameters. The entire process – from design to delivery of the finished product in June 2011 – took two years.
“Thanks to the cooperation with WACKER and the extensive expertise of the technical team for high-voltage applications, we were able to continuously improve the silicone insulators and tailor them to our customers’ requirements,” says Jalan. At the end of production, we have an almost ten-meter-long silicone composite insulator. The challenge associated with such large parts: “They cannot be made in one piece in an injection-molding machine, but must be constructed in stages – by step molding,” explains machine expert Schmid. The process was a success: the insulator giants passed the tests in February 2012. Insulators for 1,200-kilovolt high-voltage power cables were thus designed and manufactured for the first time in India by Deccan.
India’s Energy in Numbers
Lightweight and Extremely Sturdy
Silicones offer another property that is very important in such components: low weight. The finished product weighs only one tenth of what a conventional porcelain insulator would. Moreover, the silicone components are in no way inferior to their ceramic competition in terms of mechanical strength. Lambrecht: “The silicone insulators are lightweight, yet extremely sturdy. They can carry the weight of around 200 average cars.” In addition, the material is highly resilient and offers the required long-term stability of four decades. Silicones are also better protected against vandalism than brittle porcelain insulators, because they are elastic. According to an estimate by McKinsey, to prevent blackouts such as the one of summer 2012, India would have to double its electrical output from today’s approximately 200 gigawatts to around 400 gigawatts by 2017 – a mammoth task. New power plants have to be built, as well as several thousand kilometers of high-voltage power lines to distribute the electricity. Huge quantities of silicone insulators are needed for this alone – at least six per power pole. “Since the maximum span between two carriers is 500 meters, a one-hundred-kilometer line in the simplest configuration even adds up to 1,200 insulators,” calculates Lambrecht.
Lifeblood of Industrial Society
The power grid not only relies on composite insulators. Electricity distribution requires other components, such as cable accessories, which are also based on silicone elastomers. However, India’s economy can only pick up renewed pace when its power grid works reliably and covers the whole country. Electricity is the lifeblood of a rapidly modernizing society such as the Indian one. Without it, everything comes to a standstill – in India nowadays, too.