Considerations for modeling MTDC systems in transient stability programs

A description is presented of the development and selection of DC line, DC converter, and DC control models suitable for studies of multiterminal DC (MTDC) systems with transient stability programs. Features of MTDC systems and relevant characteristics of transient stability programs are discussed, as well as experience with the models. Evidence from the design work undertaken for actual MTDC projects suggests that considerable refinement and customizing of the control are essential to meet performance and reliability goals. The choice of model would then seem to depend on the degree to which the operating strategies and control design have progressed, as well as the ability of the programs being used to accommodate them authentically. An authentic detailed model cannot be achieved before the system is designed, because in addition to DC control refinements specific to that system, it is necessary to know how the DC installation responds to faults