FIELD: electrical engineering. SUBSTANCE: ground detector for stator winding of unit generator has potential transformer whose high-voltage winding are connected in star with neutral grounded and each phase is connected to stator winding leads; its low-voltages are connected in open delta one of whose leads is connected to first pole of first regulated a.c. voltage source and its other lead is connected through measuring shunt to second pole of mentioned source. Voltages picked off outputs of selective average d.c. voltage shapers 8, 18, 21, 22 are applied to inputs of retrieval and storage devices 11, 12, 23, 24 respectively. All mentioned retrieval and storage devices are controlled by microcomputer 15 and receive control signal from its first control output simultaneously by which they memorize input voltages corresponding to single moment of time and save them for period sufficient for operation of analog-to-digital converter 14. Upon arrival of control signal at retrieval and storage devices, microcomputer 15 sends control signals to multiplexor 13 from second control output and to analog-to-digital converter 14 from third control output. In the process, outputs of retrieval and storage devices are connected in turn to input of analog-to-digital converter to convert analog-signals into digital codes and to enter these codes in microcomputer. So, first input of multiplexor 13 is supplied with voltage from output of first shaper through first retrieval and storage device 11; this voltage is proportional to RMS current I1 at frequency f1 set up by first source 4; second input of multiplexor is supplied with voltage built up by second source. Microcomputer solves set of equations and finds insulation resistance which is displayed by final element 16 and digital display 17. EFFECT: improved design. 3 cl, 1 dwg
