Generator switchgear and busduct for the Kaprun main stage power plant

EQOS Energie made a significant contribution to the “Kaprun main stage power plant efficiency enhancement” project on behalf of Verbund Hydro Power GmbH. The measures implemented by EQOS Energie were necessary, as the performance of the Kaprun main stage power plant has now increased by 40 MW to 260 MW with the help of purely technical measures.

It was the task of EQOS Energie to realise the energy transmission between the two refurbished generators G3 and G4 and the new 200 MVA three-winding transformer. In this respect, the key components are the two generator switchgears with the synchronising circuit-breaker. he rating data are impressive with 5,500A rated current and 72kA short-time current. The two generator switchgears and the 12.5 kV auxiliary power supply switchgear, which are also supplied by EQOS Energie, are each completely controlled and interlocked with a Symap Compact+ protection and bay control device programmed by EQOS Energie. In addition, EQOS Energie supplied and installed the 400 V AC and 220 V DC switchgears, which were to be renewed during the project, and replaced significant parts of the auxiliary power supply medium-voltage cabling.

A particular challenge was posed by the insertion and installation of the multi-curved busbar elements in and through the narrow, approx. 17-metre-high fresh air duct. There had to be enough space in the narrow shaft for scaffolding in line with occupational safety requirements, already installed part of the busduct and the insertion of further busbar elements. A cross-divisional installation team proved its worth in this respect. Colleagues from the overhead line division were able to successfully contribute their experience and expertise in work at heights and heavy load installation to an energy technology division project.

During the commissioning, the new high voltage test system was successfully utilised, among other things. In addition to partial discharge measurement, µOhm resistance measurement and thermography, the usual measurements and tests were also carried out.