Power system transients

The steady state load limits of a power network may be examined by familiar methods of analysis. However, the instability of a system with one or more elements working close to these limits sets lower values of power at which the system can be expected to give satisfactory operation under the sudden changes in load or connections which it must successfully sustain in operation. This paper presents methods for the analysis of power systems under transient conditions. A qualitative discussion of the problem is given, followed by an outline of a point-by-point scheme of analysis which takes into account the inertia of machines, field transients, etc. The value of this scheme depends upon having available rapid methods of analysis applicable to conditions prevailing at a given instant during the transient. Therefore, there is also included a description of the methods which have been found advantageous, notable among which is a superposition method of solving systems by means of charts. This is a powerful means of attacking complicated systems. The method of point-to-point analysis is applied to specific types of networks as examples. There is also given an extension of approximate methods of analysis presented previously. The paper is confined to the exposition of the methods of analysis which we have found convenient and powerful.