Performance modelling of generator sets during load acceptance

Traditional generator models, which represent large thermal plants, are simplified on the basis that they are not subjected to large fast-acting electrical transients. Typically these models use a fifth-order synchronous machine and a lower order prime mover model. Although these models are generally suitable for large power system analysis with relatively small-scale disturbances, when these models are used within small networks they cannot be expected to remain representative. When diesel gen-sets are used as a backup supply, they may be expected to supply full rating in a single step from no-load. A gen-set will experience much larger speed and voltage transients than a large thermal plant and a high degree of modelling must take place. This paper presents a gen-set model of engine, synchronous machine, speed governor and voltage regulator.