Displacement governing in a 2-machine systemߝa hybrid simulator study

The paper describes a study of the operation of displacement governors in the classical 2-machine system. A previous study of an isolated synchronous alternator with its prime mover controlled by this type of governor indicated that, with properly designed governor parameters, a great improvement in the dynamic-stability limit of the alternator could be effected. The object of this companion paper is to determine whether the optimised parameters of the isolated governed machine may still be employed and, if so, the effect on the system stability limits. Owing to the severe idealisation required to facilitate analytical treatment of this subject, the problem was studied on a power-system simulator, in which the alternator set and its prime mover were represented by a d.c. analogue, and the transmission system and load were represented by a l6kc/s network analyser, the two analogues being interconnected by coupling circuits. To provide some theoretical verification of this work, stability criteria have been developed by applying the Routh-Hurwitz stability criteria to the linearised equations of the idealised system. The work described clearly shows that an increase of 100% in the maximum load power that can be delivered in a 2-machine system may be achieved, provided that optimised gain-compensated governor stabilisers are used.