Simulation of internal faults in high-voltage cable-wound generators

An accurate determination of internal fault currents is needed for the design of adequate protection schemes for cable-wound high-voltage generators. A model of a synchronous machine in direct phase quantities for an internal single phase-to-ground fault is presented. A single phase-to-ground fault at the first turn near the generator neutral is simulated when the generator is either isolated or connected to a power system network. Simulations are also performed for when a single phase-to-ground fault occurs at different locations along the winding. The simulations are applied on the world´s first high-voltage cable-wound generator installed at Porjus, Sweden which is rated at 45 kV and 11 MVA.