Digital Simulation of Multimachine Power Systems for Stability Studies

A digital simulation technique suitable for detailed analysis of both large and small disturbances on extensive power systems is presented. The analysis employs a hybrid reference frame for statement of the problem and for its solution. The equations of the interconnecting network are expressed with regard to a synchronously rotating common reference frame and are treated with the aid of matrix methods. Synchronous machine equations and equations of the voltage regulator and of the speed governor are solved in Park´s reference frame fixed to the field of each individual machine. Provision is made for representing different machines in different degrees of detail. An efficient numerical technique for solution of the resulting complex nonlinear equations describing the behavior of the complete power system is introduced.