A New Control Method for Multiterminal DC Transmission

摘要

A new control scheme for parallel multiterminal dc systems is proposed. The scheme is divided into two separate functions: a supervisory control called the Systems Monitor-State Predictor (SMSP), which determines the steady state operating point of the system from ac volage measurements, power requirements at the converters, and the dc network configuration; and the feedback controllers which drive the system to the desired operating point supplied by the SMSP. A systematic method is presented for calculating local feedback gains based on optimal control theory. It is shown that the use of feedback measurements is possible with negligible loss of dynamic performance. A detailed hybrid computer simulation of a four-terminal dc system is used to demonstrate the performance of the new control scheme during steady state operation and for large system disturbances. It has advantages in speed and flexibility over the conventional approach through its use of system voltage measurements. The method can be implemented as an on-line control using a small central computer.