ABSTRACT
When diagnosing the condition of HV insulation systems of electrical machines, their insulation current, resistance, capacity, loss, and absorption factor are most often determined. Either high-voltage Schering bridges or high-voltage impedance meters are used to measure the capacity and loss factor of HV insulation systems of electrical machines. The low-voltage part of the bridge consists of a resistor and the resistance and capacitance decades, which balance the bridge, so that there is a minimum voltage on its measuring diagonal, which is indicated by the zero indicator. If the non-phase-shifted digitized harmonic excitation HV voltage multiplies the digitized voltages and currents of the measured and normal impedances, then the mean value of the products of these voltages and currents with the excitation signal determines their real components. The dielectric absorption of an insulator is caused by a delay in the polarization of the dielectric as the polarity of its electric field changes.
