“Decentralized power generators have to cope with disturbances in the power system in a supporting and reliable way“, explains Dr. Philipp Strauß, deputy head of the institute and head of the division Systems Engineering and Distribution Grids at Fraunhofer IEE in Kassel. The institute performs the measurement of generating plants according to the requirements of the interface to the power grid for the so-called type-specific unit certificate. This certificate is prepared for each type, e.g. a combined heat and power unit (CHP) or a photovoltaic system, and precedes the certification of complete systems. If required, the modelling for the simulation of the entire plant can also be carried out. “Our laboratories are used for developing components and systems as well as for final accredited tests”, describes Strauß.
According to the recent revision of the German VDE grid codes the laboratories of Fraunhofer IEE were now completed with an over-voltage-ride-through (OVRT) test equipment for a maximum power of 6 MVA. Since 2011 Fraunhofer IEE is testing power generators concerning grid compliance including their fault-ride-through (FRT) behavior.
“The transformer-based, mobile test container was successfully developed in cooperation with KoCoS Engineering GmbH”, explains IEE project leader Nils Schäfer. The new OVRT test container allows generation of short-term over-voltage events of up to 140 % of nominal voltage. The OVRT as well as the UVRT container are designed for mobile utilization and can be deployed in field measurements. Both have a power capacity of 6 MVA and can be installed in the medium voltage level at 20 kV or 10 kV nominal voltage. The new testing equipment was successfully set in operation in summer 2019; first tests have been accomplished with CHP units.
Beneath testing of grid compliance and studies on grid dynamics, Fraunhofer IEE offers services regarding conceptual design, development, implementation and operation of mobile testing equipment. Together with partners, services range from support and supervision to turnkey solutions.