SIMULATING ABNORMAL AND EMERGENCY OPERATING MODES OF POWER TRANSFORMER ELECTRICAL NETWORKS

The aim of the study is to analyse abnormal and emergency operating modes of power transformer electrical networks using a simulation model. To achieve this aim, the authors conduct an analytical review of current relay protections for power transformers; develop a simulation model of the power transformer electrical network in the MATLAB/Simulink software environment. The model allows simulating the normal, abnormal, and emergency operat-ing modes of the power transformer electrical network. The paper performs calculations of short-circuit currents and parameters of current relay protection operation for the power transformer electrical network; develops a simulation model of the power transformer relay protection and automation, which allows analysing the behaviour of current relay protections under abnormal and emergency operating conditions. The work carries out a methodology for ana-lysing abnormal and emergency operating modes of power transformer electrical networks; fulfils simulation experi-ments to model the normal operating mode of the power transformer electrical network, as well as abnormal and emergency operating modes, during which the current cutoff, maximum current protection, and ground fault protec-tion are activated. The result of the experiments are oscillograms of currents in the electrical network for each oper-ating mode. The analysis of the obtained results shows that the developed simulation model allows modelling abnor-mal and emergency operating modes of the power transformer electrical network, adequately reflects the algorithms of its current relay protections, and can be used in operating electrical networks and training energy personnel.