Optimised topology design and comparison for offshore transmission

This paper presents an economical and technological comparison between a conventional point to point (PTP) VSC-HVDC system and a DC mesh grid. A case study based on Dogger Bank Creyke Beck is used for this investigation. In the economic comparison, three main components are considered- VSC converter, DC cable and DC circuit breaker. The cost of losses is analyzed and the investment cost is estimated. Simulation using PSCAD/EMTDC is undertaken to support the technology assessment. The system redundancy during normal conditions is presented while the performance of each topology during fault condition is also illustrated. It is concluded that a DC mesh grid is more flexible in technology aspect and saves the costs.