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Key switch secure substation

The huge power lines that protrude from the wall in the Großgartach substation and merge into the overhead line are impressive. The dimensions of the routes are comparable to the motorway network. Here, the maximum voltage of 380,000 volts from various power plants, wind and solar systems from the European grid is distributed and transformed to 110,000 volts for further distribution to regional distribution grids, analogous to federal/country roads. Großgartach is just one of 50 substations operated by the transmission system operator TransnetBW, which secures the power supply for around eleven million people in south-west Germany.

Systems updated

Substations must be well secured. For this reason, a new system to protect against maintenance and repair work was installed in 2021/22 during the conversion in Großgartach. Key switches from Kraus & Naimer GmbH in Karlsruhe are used, which not only ensure safety but also greatly simplify work processes.

"Until now, the electrical drive had to be blocked after activation by the main control line, e.g. at a switch. In a so-called gas-insulated switchgear, this is sometimes only possible by working at a height of up to eight meters in areas that are difficult to access," says Martin Steinhart from TransnetBW. With the installation of the Kraus & Naimer key switch centrally on site in the control cabinet, the drives of the switches can be deactivated in order to secure them against being switched on again.

The CA20 key switches with a customer-specific special program fulfill a double function: By using a locking system, individual fields (drives) are "locked off" from one another, which prevents confusion when working in the switchgear. “Each switch key only fits certain padlocks, with which the system is locked again on site. This ensures that employees can only access the areas that they have previously switched off and secured themselves," explains Johann Roshau, area sales manager at Kraus & Naimer.

Requirements like these and the individual lettering of the front plates have been part of everyday life at the international switch specialist Kraus & Naimer since 1907. In addition to a wide range of standard switches, special switches for a wide variety of customer requirements are designed and manufactured in Germany and five other countries around the world. Touch panels for digital solutions as well as functional handles and enclosures are also part of the range.