Assessment of excitation control by simulation

The method for power system transient simulation adopted by Siemens Power Generation Ltd. (SPGL) since 1991 was largely inspired by the approach described by R. Podmore and R.J. Fleming (see IEE Proc., vol.121, no.10, p.1165-7, 1974). This paper describes a computer program, written in FORTRAN IV, in which the emphasis is placed on flexibility in the modelling of generators and controllers. Power plant is modelled using differential equations, based on block diagram representations, and the solution of the loadflow problem is algebraic. At the time, the application of the program was limited to small/medium sized networks by run times. This satisfies the needs from a manufacturer´s point of view. The approach allows us to concentrate on what we know about whilst enabling most of the characteristics of actual transmission systems, relevant to the effects of prime mover control on transients, to be represented. This is in contrast to the needs of large utilities whose responsibilities require the study of large networks, who need detailed knowledge of alternative network structure and data, and also have the sometimes difficult task of getting data for generator controllers to fit the limited range of structures allowed by the available power system analysis software. The method used by SPGL exploits the features of Matlab/Simulink for modelling and simulation using block diagram representations of machines and controllers