FIELD: measuring technology.
SUBSTANCE: invention refers to methods of testing and controlling the insulation resistance of unearthed (body) direct-current power mains. In a direct-current main with an isolated neutral, there is measured pressure between "earth" and poles of a direct-current source and measured currents flowing in main attachments to one pole of one and then the other resistive elements of an attachment. It is combined with voltage grading on poles. The derived voltages and currents are used to calculate the insulation resistance. There is a differential current sensor designed for the declared device. When supplying voltage to a measuring winding, a constant component of the magnetic field is observed in a magnetic circuit of said sensor that invokes zero shift of the hysteresis loop. The voltage signal from the measuring winding amplifies and travels on an input of an analogue-digital converter.
EFFECT: invention allows improving test accuracy of insulation impedance, including for each pole separately.
3 cl, 6 dwg
