Activation of Curative Actions as Contribution to System Security in DC-Interconnected Distribution Systems

The increasing amount of renewable energy generation within distribution systems has become a challenge for power system operation. Connecting several distribution systems via VSC-based DC-interconnections has been identified to be an effective alternative to conventional grid expansion to relieve power systems. Considering curative system security as part of future power system operation the connected distribution systems suffer from interactions during fault conditions caused by the converter responses. Therefore, this paper introduces initially the concept of curative system security and presents two approaches for curative actions. The impact of the different approaches on system dynamics will be analyzed and compared on basis of a numerical case study to reveal the need of a matched operational planning for interconnected distribution systems.