FIELD: electrical measurement hardware.
SUBSTANCE: invention can be used for on-line control of single-phase unloaded-winding transformer state under operating conditions. The proposed method consists in recording arrays of instant magnitudes of input voltage, output current t2 and output voltage. Inductance is calculated, the value obtained is averaged over a period. Arrays of instant input current i1 and voltage at unloaded winding is recorded. Now the currents and voltages are reduced to the primary circuit. The input and output currents are differentiated to produce arrays 
and 
Array u1 represents a difference between instant input voltage and reduced voltage across unloaded winding and array u'2 represents a difference between instant reduced voltage across unloaded winding and reduced output voltage. Times t1 when i1(t1)=0, times t2 when i'2(t2)=0, times t3 when 
and times t4 when 
are recorded. Now, the transformer primary and secondary dissipation active resistance and inductance 
are calculated. The magnitudes obtained are averaged over the period and obtained mean magnitude relative departures from reference magnitudes red off a good transformer are calculated. Now, the obtained results are compared to the preset setting and, if even one departure exceeds the said setting, the controlled transformer winding is taken to be faulty.
EFFECT: higher reliability and efficiency control.
2 tbl, 5 dwg
