A system, method and computer program product for monitoring including detecting internal faults especially inter-turn faults of a synchronous generator and thus protecting the synchronous generator. The synchronous generator includes a winding for each phase of a power network, a terminal for each phase arranged on a terminal side of the synchronous generator, and connected to the respective winding, the terminals on the terminal side are connected to an electrical power network, and the synchronous generator is arranged to input power to the electrical power network by means of the terminals.