Digital Simulation of Synchronous Machine Transients

When synchronous machine transients in an extensive system are to be accurately calculated, many problems arise for which the information required to resolve them is not available. The resulting accuracy will depend upon the assumptions used not only in the development of the machine model but also in the way in which the incomplete model is solved. The primary problems involve the manner in which the machine terminal relations are related to those of the system and in the handling of the various torques produced in the transient operation. The state of the art of machine analysis is now such that synchronous machine transients are fairly well understood and calculations may be reasonably comprehensive. The system representation is, however, not capable of accepting the information available from the machine with the result that a satisfactory marriage is difficult. Some of the inadequacies of large scale stability analysis as it now exists and some of the precautions and planning that should be observed before embarking upon extensive studies or in drawing conclusions from such studies are covered here, in a philosophic and general manner.