Turbogenerator transient behaviour under large system disturbances : a study of performance improvements by fast acting controls

Abstract

Mathematical models of varying complexity for representing turbo- generators and associated excitation and prime mover control systems are developed. Special reference is made to the application of these models for digital computer solution to determine turbogenerator transient performance-under large system disturbances. A parametric study, of the effect of differing generator designs and control systems configurations, on the transient behaviour is performed, using the digital computer model, In particular, the capabilities of the latest high speed control systems, such as, thyristor exciters and electrohydraulic governors, are assessed, Novel methods of stabilisation of these systems and the effects of both single and combined control action are investigated. In choosing the most appropriate computer-model, the aim was to achieve the highest possible complexity, taking into account the limitations on available machine data, A full account of the results of fault tests on a full scale turbogenerating system with thyristor excitation, in which the author participated, is given, These were intented to verify some of the control policies developed, and provide an accuracy check on the computer programme to give confidence in the modelling technique for future simulkations. Fast response instrumentation for obtaining specialised feedback signals for the site tests is described, together with a full set of equipment for laboratory investigation on a model power system. Although a number of difficulties with the instrumentation were encountered in the tests, the results serve to illustrate the capabilities of fast thyristor excitation systems, and the high degree of accuracy obtained by the digital computer simulation techniques.