Supply of an Entirely Passive AC Network Through a Double-Infeed HVDC System

A double-infeed HVdc (DI-HVdc) system, combining a conventional HVdc transmission and voltage-source converter-based HVdc (VSC-HVdc) technology, is proposed in this paper for supplying an entirely passive ac network. The new concept and detailed model for starting HVdc using VSC-HVdc is provided and control strategies of the whole system are designed. Aiming to validate the steady state, dynamic and transient performances of the proposed DI-HVdc system, the process of starting HVdc using VSC-HVdc and ac faults conditions are simulated in PSCAD/EMTDC. Simulation results show that HVdc can start successfully using VSC-HVdc and the whole system has favorable dynamic and transient performances under ac faults conditions. Finally, the prospects of DI-HVdc are discussed.