Influence of Quadrature-Axis Reactance of Large Turbine Generator on Operation

Two-pole large generators are extensively used in power utilities. Growing demand for electric power in recent years has led to substantial increases in the capacity of generators. To meet this trend, we have manufactured 2 pole turbine generators in 900,000kVA to 1,200,000kVA classes. As the capacity of generators becomes larger, equivalent circuits are increasingly expected to improve their precision in estimating operation characteristics. Park model has been widely used as an equivalent circuit model. Park model with quadrature axis transient reactance x'q is claimed to be useful for accurately estimating the load rejection characteristics of turbine generators. However it is difficult to measure the x'q, few studies have been reportedly carried out based on measured data. As one of the few examples, we have conducted a measured data on a 500,000kVA class generator. Recently, the authors obtained the test data of x'q of 900,000kVA class generator. In this study, based on these data, we studied the effect of x'q, using the finite element method (FEM) and transient analysis program (EMTP-ATP).