Practical manual contains basic concepts and description of power supply systems: diagrams of construction, calculation, selection and installation of electrical equipment. Practical application is presented in solving the problems of calculating electrical loads, choosing the number, power, type and place of installation of TT power transformers, input devices, choosing voltage, devices and devices for control and protection, as well as external and internal power supply schemes and electrical equipment of the power supply system. It will be useful for electrical personnel engaged in the design, operation and installation of electrical networks and electrical equipment of power supply systems, as well as students of electrical specialties.