Construction of a DC Current Injection Generator for HVDC Long-Term Tests up to 5000 A DC at 660 KV DC Potential

Abstract

HVDC components have to be tested with current and voltage simultaneously to test space and surface charge effects adequately. The DC current injection at high voltage potential is the best choice to test these effects on HVDC components according to their later operation in the grid. No commercial generators to solve this task are available. The capacitive current injection is a reasonable concept for DC current injection, since high current and high voltage ratings by stacking of several components can be achieved. It consists of a feeding unit, the transmission path and the rectifier at high voltage potential. The contribution shows, how the generator components can be built and which technical parameters are required inside the generator. The overall goal of the project is the upscaling of the concept up to 5000 A DC current on a high DC voltage potential of 660 kV. Challenges and solutions during the design phase of the upscaled generator are discussed. Pictures of the generator components are shown, as well as first experiences with the upscaled generator. The contribution demonstrates that this generator concept for DC current injection at high voltage potential is technically feasible for high equipment ratings.