A co-ordinated large-signal modulation strategy for multi-infeed HVDC systems

A coordinated large-signal modulation strategy for multi-infeed HVDC systems is presented in this paper. With the HVDC systems being treated as a variable admittance connected at the commutation busbars, the control law of HVDC system´s transfer power can be derived using optimal control theory. A two level hierarchical control structure is assumed for the rectifier and inverter side AC system respectively. The control of constituent HVDC subsystems can be better coordinated by the consideration of the AC commutation voltage included in the optimized performance index, and both the performance of rectifier and inverter side AC systems are considered.