METHOD OF FAST AUTOMATIC SWITCHING ON THE CONSUMER SECONDARY POWER SUPPLY Russian patent published in 2018 - IPC H02J9/06 

FIELD: electrical engineering.

SUBSTANCE: according to the method, the voltage is measured on the buses of the main and secondary power supplies and the angle between the voltage vectors of the direct sequence of the phases of the main and secondary power supplies; determine the direction of power in the phases at the input of the main power supply bus; switch the bus power from the main power supply to the secondary one if there are no blocking signals from other devices and when the direction of power is changed at the input of the main power source from the bus to the voltage source on the buses of the main power source is less than the preset level or the angle between the direct sequence voltage vector is greater than the preset level. In this case, the currents flowing through the inputs of the main and secondary power supplies and the zero sequence voltage on the buses of the main and secondary power supplies are measured; determine the line voltages on the buses of main and secondary power supplies, special line voltages, the direction of transmission of the total power in phases at the input of the main power source. Switch the bus to a secondary power supply: if there is no change in the residual voltage on the busbars of the main and secondary power supplies and any of the phase currents flowing through the input of the main busbar section, more than the set value, while if, for a specified period of time, the value of all phase currents does not change by less than the preset value, switching to a secondary power supply is prohibited; when the direction of transfer of the total power at the input of the main source is reversed, or the values of any of the phase currents flowing through the input of the main busbar section, less than the set value and any line voltage on the bus bars of the main source is less than the set value, or the magnitude of the angle between the voltage vectors of the direct sequence of the main and secondary power supplies is greater than the set value. If during a given time the value of the phase currents flowing through the input of the main power source is less than the set value, then this condition is blocked until any of the currents changes more than the set value; if there are at least two line voltages on the secondary power supply, there is more than the set value and synchronism between the voltage vectors of the main and secondary power supplies.

EFFECT: excluding the possibility of creating an artificial double earth fault at the time of switching to a secondary power supply.

5 cl, 1 dwg