Abridgment of progress in the study of system stability

In the second part of this paper and in the appendices, attention is given to simplified methods of treating the problem of system stability. Methods which have been found useful in making many system studies are recorded. These methods have had considerable verification by tests both on a model system and on large operating systems and have been simplified to such an extent that many operating companies are now finding it to their advantage to undertake the work of making careful studies of their own systems, just as they now make short-circuit studies which formerly were thought too difficult and too highly theoretical. The first part of the paper gives some comments and conclusions of the authors and their colleagues as a result of many such system studies as well as studies involving more detailed methods, and also as the result of practical experience through contact with various operating companies. Some of these comments are based directly upon an example which is given in detail in Appendix I.