Modelling of control of a doubly-fed machine in transient stability analysis

The control of active and reactive power of a doubly-fed machine (DFM) can be-due to the application of power electronics-very rapid, comparable to the control of FACTS devices. Besides DFMs in pumping-storage plants will become an important part of Slovenian electric-power system and it is important to know how these machines are working. This paper presents how to model a control of a DFM in a pumping-storage plant to be included in various computer programs for power-system dynamic analysis. We constructed the model of turbine, turbine governor and the model of control of the converter that connects rotor to the network, while the model of the machine itself is already internally modeled in these programs. Results of dynamic analyses show responses of the DFM to step changes in electric-power system and the ability of rapid changes in its operation. The application of the proposed model shows that the model is adequate for the analysis of power-system dynamics. The results show superior dynamic characteristics of DFM.