A DC board (DCB) of a distribution substation is designed to distribute a direct operating current for powering relay protection devices and equipment automation, including electromagnetic blocking of switching devices; for power supply of solenoid circuits of high-voltage switches, as well as for power supply of various communication devices, telemechanics, automated metering devices for electrical energy. Power supply of DC circuits is carried out through rectifiers and from a storage battery when the AC auxiliary voltage disappears. They can be used at power plants, TP and RP.