Through the first part of the paper, industrial plants, technological equipment and types of industrial plants are theoretically defined. Oil refineries are also defined, refining procedures and products are described. In the second part of the work, attention is paid to the design of the electric power supply and distribution system in the oil refinery, as well as the elements of electric power plants. The concept of selection and the importance of certain parts of the plant for constant power supply are explained. The final part shows the importance of the stability of the power supply itself and the possible solution of achieving a constant power supply through other sources and the use of a system for quick load shedding.