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HVDC transmission systems like cables or gas insulated systems are of great interest for future grid expansions. They are usually type t ested in one-year long-term tests, to ensure lifetimes up to 40 y ears and more. HVDC equipment always has to be tested with voltage and current at the same t ime to investigate temperatur e dependent space charge eff ects inside the insulation material. Eve n though the HVDC equipment in the grid is operated with DC current and DC voltage, laboratory tests often have to be performed with AC current heating due to laborato ry limitations. The following report shows the technical limits of AC current injection and presents s olutions for DC current injection on high voltage potential. The solutions are described and compared to each other. Furthermore, the reportshows the status of actual research and prototyping for this new generator type. |
