Background. The principle of operation of the known versions of ground fault protection systems in stator windings, based on the use of third harmonic in EMF (electromotive force) of generators, is usually based on a simplified idea of uniform and linear distribution of EMF and, consequently, the voltage of this harmonic along the stator winding. However, as experimental data presented in several scientific papers show, such simplified assumptions do not always reflect the actual distribution of third harmonic voltage in stator windings. This can lead to false operation of these protection systems during non-ground fault conditions. Due to the difficulties to conduct experimental measurements on an operating generator, it is essential to develop a simulation model that accurately represents the actual behavior of the third harmonic voltage. This model should take into account the operational mode and design characteristics of the synchronous machine. Such a model is necessary to both develop efficient protection against ground faults in the stator windings and assess the technical effectiveness of existing generator protection against this type of failure.
Materials and methods. To develop a simulation model of a synchronous generator, the authors have used the SIMULINK environment in the MATLAB software package. The model has been developed based on the theory of electrical machines. To validate the model, the authors have used typical characteristics and experimental data from scientific publications and educational and reference books.
Results. A simulation model of a synchronous generator has been designed, which takes int account complex and non-linear nature of the third harmonic voltage distribution along the stator winding. The model considers the design and operation mode of the machine as well as the location of any ground faults.
Conclusions. The developed model can be used to both develop protection against ground faults in the stator winding of generators based on the third harmonic, which has higher technical perfection compared to existing designs, and evaluate the effectiveness of current protections against this type of damage.