Selected problems of autonomic operation of three-phase synchronous generators

The paper presents selected problems related to autonomous operation of three-phase synchronous generators used in diesel-electric sets appropriated to emergency supply of various receivers of electric power located in stationary, communal, or industrial objects in case of failure of the basic electric power supply. A set of equations adapted to analysing the conditions of autonomous operation of three-phase synchronous generators is presented (in the conditions defined by means of computer simulations). The equations are presented in the form enabling analysis of the operation conditions of the generators driven by combustion engines of oscillating rotational speeds that, inducing variations of the frequencies of induced electromagnetic forces. The equations are so formulated as to allow for analysing operation of the generators under various operation conditions, particularly forced by asymmetric impedances of the receivers. The equations enable analysis of non-symmetric conditions of the generator operation states, among others, in the cases like single-phase asymmetric loads or internal asymmetry giving rise to electromotive forces of symmetric components of negative and zero sequence. The equations enable calculating the active and reactive power delivered by the generators under various frequency values and asymmetric conditions. The formulated equations were used for calculating characteristic parameters of generators under various operation conditions