An explicit formulation for synchronous machine model in terms of the manufacturer data

Abstract

There are numerous formulations and methods for representing synchronous machine (SM) in stability studies. However, most of them need to convert manufacturer's data given in the form of transient/sub-transient time constants and reactances, to the equivalent circuit parameters as resistances and leakage reactances of rotor windings. This study derives a new explicit synchronous machine model formulation by direct utilization of the transient/sub-transient time constants and reactances in the SM model formulation. Firstly, state-space equations are derived with flux linkages as state variables. Then, some entries of coefficient matrix are determined in terms of the manufacturer's data using short- and open-circuit time constants concepts. Other entries are calculated using this phenomenon that the flux linkage penetrates gradually into rotor core, following a sudden fault. Finally, voltage-behind-reactance (VBR) form of the proposed formulation is provided to a direct machine-network interfacing. Also, the developed formulation is compared with the Park's model in a single-machine-infinite-bus (SMIB) and 36-zone 75-machine Great Britain (GB) system using DIgSILENT PowerFactory software. The analytical and simulation results illustrate that the proposed explicit formulation is as efficient and precise as the well-known Park's model. © 2018