Scientific paper ID 893 : 2013/3

An essential guide for improving the operational reliability of synchronous generators in power plants is the use of brushless excitation system with uncontrolled (diode) rotating rectifier. Together, however, arise some problems to solve in their application. One of them is connected with its fast speed of transition processes in normal modes (forcing excitation) and emergency. Significant emergency transitional process is quenching of the magnetic field at intercoil short circuits in the stator phase winding. Then the differential protection off synchronous generator from the network. The problem remains, however, as the rotor continues to spin and the magnetic field exists. It supports short-circuit currents stator and thus burning phase stator winding. It is therefore necessary field current and the magnetic field rapidly reduced to zero. This is precisely the process of extinction. On this issue, there are very few publications to consider it only partially. This paper provides a possible solution. It is to bring in inverter mode thyristor rectifier in the excitation of the exciter coil and circuit solution for both contactless damping resistor in the excitation circuit of synchronous generator. Outlines the relevant analytical dependencies amending excitation currents.