Rotor Damping Effects in Dynamic Modeling of Three-Phase Synchronous Machines Under the Stator Interturn Faults—Winding Function Approach

Condition monitoring is used for early detection of incipient faults in electrical machines. Accurate modeling and simulation of the faulty machines can help to design effective condition monitoring systems. Three-phase synchronous machines (TSMs) are widely used for electrical power generation at power plants. Winding function theory offers effective, quick, and rather simple method for modeling and simulation of faulty electrical machines; however, this method only includes real windings of the machine. Rotor damping effects have important role in dynamic performance of the TSMs. Fictitious short-circuited windings (damper windings) on the rotor direct and quadrature axes are used to model these effects in the Park's vector model. This paper offers an approach to include similar damper windings in the winding function approach for modeling TSMs with interturn fault in the stator winding. Simulation results show creation or amplification of some frequency components in the stator line current as well as the rotor field current due to the interturn fault whose frequencies are equal to the rotor speed and its integer multiples. The frequency components are also present in the circulating fault current within the shorted turns. Experimental results approve the simulation results.