摘要 |
FIELD: electric engineering. ^ SUBSTANCE: method includes, if voltage in power grid is abnormal, commutation of relay windings power with advance in such a way, that commutation of outputs of transformer windings by relay contacts occurred in area of transfer through zero of commutated current, if actual value is above threshold level, and if below threshold - then during transfer through zero of input voltage. Control is performed by microprocessor means. Commutation of contacts is performed close to point of current transfer through zero without forming of arcs on commutated contacts, or close to zero point transfer for input voltage without forming sparks on commutated contacts. ^ EFFECT: higher reliability, lower interference. ^ 3 cl, 1 dwg |