COMMUTATIONAL DEVICE Russian patent published in 1995 - IPC

FIELD: electrical engineering. SUBSTANCE: commutational device includes commutation unit ensuring connection of load to network. Its control input is linked to output of former of controlling voltage manufactured in the form of RS flip-flop. Device also has rectifier and two threshold elements with different threshold levels connected to its output, outputs of elements are terminated at R and S inputs of flip-flop. Commutation unit has pair of power transformers connected in parallel opposition controlled by circuit incorporating transformer which primary winding is coupled to input power leads of unit and is shunted by third thyristor which controlling electrode is linked to control input of unit. First leads of secondary windings of transformer are connected to input power lead of unit, second leads to controlling electrodes of power transformers. Commutational device realizes hysteresis relay law of control over commutation unit on the basis of two-threshold estimation of level of network voltage which ensures stable operation of device when load is linked to network at start of extrapeak period of operation of power system with change of voltage higher than first threshold level and disconnection of load at start of peak period with change of voltage below second threshold level. EFFECT: ensured reliability and safety of operation of power networks. 2 dwg