FIELD: electricity.
SUBSTANCE: device includes miniselector with three inputs supplied with three sources of d.c.voltage used for detecting minimum out of three deflections of inter-phase voltage modules under normal and emergency conditions of three-phase power supply system operation. In addition, the first d.c. voltage supplied to miniselector is taken from non-sinusoidal voltage produced as a result of multiplication of the first sinusoidal inter-phase voltage by falling behind the first the second sinusoidal inter-phase voltage. The second supplied voltage is taken from non-sinusoidal voltage produced as a result of multiplication of the second sinusoidal voltage by the third sinusoidal inter-phase voltage generated as a result of multiplication of the first reference sinusoidal inter-phase voltage by the third inverse sinusoidal inter-phase voltage.
EFFECT: increased sensibility.
4 dwg
