Grids That Communicate - Wacker Chemie AG

Grids That Communicate

Testing a composite hollow-core insulator made by Reinhausen Power Composites.

In order to fill the cavity without bubbles, RPC injects the liquid POWERSIL® Gel C 670 into the composite hollow-core insulators from below. To do this, the gel is added under slight excess pressure and is thus already compressed to some extent. “With a precisely metered excess pressure, we provide additional assurance that the gel will always snugly fit the form of the pipe wall, even in the depths of a Siberian winter,” explains Merten. After the gel is filled, it cures at room temperature within approximately eight hours.

As a soft and compliant material, the compressible gel offers the embedded fiber-optic cables optimum protection against external mechanical influences. For Merten, one thing is certain: “In our new, special composite hollow-core insulators, the fiber-optic cables are locked up safe and sound. In POWERSIL® Gel C 670, we have found the ideal potting compound to suit our needs.” Under its POWERSIL® trademark, WACKER offers special silicones for transmission & distribution applications – alongside silicone gels, these include elastomers and silicone coatings.

“In POWERSIL® Gel C 670, we have found the ideal potting compound to suit our needs.”

Dr. Armin Merten Head of Development, Reinhausen Power Composites GmbH
An RPC employee testing an insulator.

First Batch Production

Reinhausen Power Composites also uses a WACKER silicone rubber for the manufacture of the composite hollow-core insulators’ sheds: the two-component liquid silicone rubber POWERSIL® XLR® 630. RPC sprays this low-viscosity silicone onto the GRP pipe under relatively low pressure. POWERSIL® XLR® 630 was designed specifically for this procedure, which is widely used in the sector.

“We have much more than a simple supplier relationship with WACKER,” explains Merten. “We particularly value that WACKER SILICONES’ technical service engineers are always on hand to resolve our technical queries and problems. We can rely on expert technical support in the development of new products, too.”

By now, the first batch of these composite hollow-core insulators with integrated fiber-optic cables is in operation. As part of a modernization project, they are used together with optical instrument transformers in 110-kilovolt substations in New Zealand. The hollow-core insulators used there are approximately 1.5 meters tall and have an internal diameter of around 15 centimeters.

Composite hollow-core insulators with integrated fiber-optic cables can do even more: the cables’ optical fibers can also be used as light and temperature sensors. So, since fiber-optic cables do not just transport signals, but also deliver information themselves, the new, special composite hollow-core insulators are in principle suited to monitoring other electrical equipment. They make it possible to detect arcs that occur if there is a malfunction, for example. This can help in identifying faulty equipment, which can then be switched off automatically – another step toward smart grids. WACKER will continue to support the development with tailor-made silicone products in the future, because the application potential of the new composite hollow-core insulators is by no means exhausted yet.