FIELD: electric measurement technology. SUBSTANCE: device has three-phase power supply, three-phase circuit-breaker, three-phase testing transformer, three-phase synchronous grounding switch, three-phase transformer under test, three voltage dividers, four current-metering shunts, voltage average computing unit, current derivative computing unit, dividing unit, period inductance average computing unit, deviation computing unit, setting unit, voltage derivative computing unit, second current derivative computing unit, unit for evaluating indeterminate forms following L-Hospital rule. EFFECT: enlarged functional capabilities. 3 dwg
