Curative Actions by embedded bipolar HVDC-interconnections

Abstract:
The erection of embedded HVDC-systems, based on Modular Multilevel Voltage Source Converter (MMC-VSC) technology, provides a support of the existing AC-system by means of active power transmission and reactive power provision. Regarding system operation, the resulting hybrid AC-HVDC-system requires an expanded security assessment to address the outages of converter, converter poles and DC branches. In order to ensure a high exploitation of thermal transfer capacity, this paper proposes the application of curative actions in case of these new contingency types. The resulting approach includes an application of security constrained optimal power flow calculations. Selected case studies describe the positive effect on system security.