Protecting Sensitive Measurement Heads
Like everything else in high-voltage technology, the equipment used in the metrological monitoring of the grid depends on reliable electrical insulation. All of the equipment’s live parts – usually the entire measurement head – must be insulated from the ground and grounded equipment and are often positioned on a hollow-core insulator. “Where measuring instruments are operated outdoors, which is the case in many high-voltage substations, operators are increasingly relying on silicone composite hollow-core insulators,” says Dr. Armin Merten, head of development at Reinhausen Power Composites GmbH (RPC). This Bavarian company, headquartered in Regensburg, is one of the world’s leading manufacturers of silicone composite hollow-core insulators.
New-generation measurement heads deliver an optical signal; many measurement heads also require light in order to create information. Fiber-optic cables transport the light. They connect the measurement head to the connection point of the communication system. Up to now, the fiber-optic cables have been guided via a so-called insulator string – rod insulators joined together in a chain-like manner. The insulator string is an additional component alongside the post insulator that carries the measurement head. “The sensitive fiber-optic cables cannot simply be suspended freely, but must be mechanically supported to protect them against damage or breaking,” explains Merten. “At the same time, the support must not create an electrically conductive path to the ground or the grounded junction box. That’s why the fiber-optic cables are guided with the aid of an insulator string.”