An optimization-enabled electromagnetic transient simulation-based methodology for HVDC controller design

This paper introduces a procedure for using optimization-enabled electromagnetic transient simulation (OE-EMTS) for the design of HVDC system controls. The OE-EMTS method conducts a sequence of simulation runs of the network, guided by a nonlinear optimization algorithm. The controller parameters in each subsequent run are refined with the aim of achieving a desired performance measure, mathematically represented by an objective function (OF). The paper demonstrates a design procedure, in which the selection of the OF follows an evolutionary path. The system is first designed with an initial OF, which often results in some unforeseen negative system behavior. In the next stage, a new OF is selected, which has the potential for mitigating this negative behavior. This cycle is terminated when a high-quality design is achieved. The procedure is exemplified with the controller design for a 200-MW back-to-back dc scheme to operate within a range of inverter short circuit ratios. The optimality measure considers dynamic changes in controller set-points as well as recovery from faults.