A Method of Power System Simulation Considering Armature Transients of Synchronous Machines (Part 2)

Abstract

This paper presents new additional findings on a new power system transient stability simulation technique proposed in an authors' previous paper (Part 1). In standard simulations of short circuit faults in power systems, it is common 'to neglect transients of the transmission networks and stator circuits of synchronous machines. Therefore, it is not possible to obtain instantaneous responses of state variables of generators, by standard method. In addition, it is well known that the standard method can not evaluate backswing phenomena caused by stator transients. The new method can approximate DC offset currents that arise from stator transients, and thus, it can approximate also backswing phenomena. However, the method is based on a standard model with stator and network transients neglected.
In this paper, three problems left unsolved in the previous paper are investigated. They are: (1) an accurate estimation of a time constant for DC offset currents, (2) a treatment of unsymmetrical network during a clearing operation of circuit breakers, (3) large computation time needed in the new method. Solutions of these problems are presented in this paper. Finally, the validity of improved new method is confirmed on experimental results obtained from a Transient Network Simulator (TNS) and simulation results obtained from EMTP.