Skip to Main Content
The interaction between the controllers of h.v. d.c. convertors connected to the same d.c. system raises problems in the design and analysis of the dynamic behaviour of the convertors under transient conditions. Studies of controller behaviour can be made on d.c.-system models, but the modelling procedure is usually costly and time-consuming. For the initial investigation of suitable controller parameters for a multiterminal d.c. system, a simplified method is proposed in the paper for which a digital program has been written. The program enables the d.c.-system response to a step change of a.c. or d.c. conditions to be studied for about 200ms after the disturbance, a time period comparable with the response of most d.c.-system controllers. The a.c. system is not represented in any detail, but the d.c. system is simulated by a distributed-constant line to enable the effect of surges to be taken into account. Examples are given of the behaviour of h.v. d.c.-convertor controllers incorporating gain linearisation, staleness factors and control changeover after a voltage disturbance on the a.c. side. The paper concludes with an estimation of the accuracy of the method for initial-design purposes and the computer-storage and time requirements.