METHOD OF RESERVE AUTOMATIC SWITCHING Russian patent published in 2020 - IPC H02J9/06 

FIELD: electrical engineering.

SUBSTANCE: according to the method of automatic switch-on of voltage, voltage U_b on consumer busbars and I_PI current are measured on the switch of infeed (SIF), connected by means of SIF to working power source. SIF position is constantly monitored by first and second position relays. Angle φ between voltage U_b and current I_PI characterizing loss of power supply is determined. Voltage U_b, current I_PI and angle φ are compared with the specified values and, if they exceed them, a signal for SIF disconnection is sent. Then the first busbar coupler (BC) is switched on, current I₁ is measured in its phases and resistance is determined by the ratio Z₁=U_b/I₁. Current I₁ is compared to preset value of current I_e and resistance Z₂ with value of resistance Z_e, and if current value I₂ is more than or equal to specified value of current I_e, or Z₂ is less than or equal to Z_e, signal of disconnection of the first BC is sent through time delay t₁. If the value of current I₂ is less than the specified value of current I_e, and Z₂ is more than Z_e, then the time delay is switched to t₂ more than t₁. If after a time longer than t₂ after switching on the first BC circuit breaker it turns out that current value I₁ is more than or equal to the preset value of current I_e or Z₁ is less than or equal to Z_e, then in time t₂ after moment of current increase I₁ in phases of the first BC to I_e or reduction of Z₁ to Z_e signal is sent to disconnect first BC. Additionally, the second BC is added to the hot standby. If after disconnection of SIF disconnection signals it is switched off and there is a signal from the first or second position relay SIF and the first BC is not connected, then the second BC is switched on. Further, immediately after switching on of second BC, current I₂ is additionally measured in its phases and resistance is determined by ratio Z₂ = U_b/I₂. Current I₂ is compared to preset value of current I_e and ratio Z₂ with value of resistance Z_e, and if current value I₂ is more than or equal to specified value of current I_e, or Z₂ is less than or equal to Z_e, then time delay t₁ is used to send signal for disconnection of second BC. If current value I₂ is less than preset value of current I_e, and Z₂ is more than Z_e, time delay is switched to t₂. Further, if after switching on second BC it turns out that current value I₂ is more than or equal to specified value of current I_e, or Z₂ is less than or equal to Z_e, then in time t₂ after moment of increase of current I₂ in phases of second BC to I_e or reduction of Z₂ to Z_e signal is sent signal to disconnection of second BC.

EFFECT: technical result consists in improvement of reliability of switching of consumers, which have lost power, to backup source.

1 cl, 1 dwg