REVERSE SEQUENCE CURRENT TRANSDUCER Russian patent published in 2014 - IPC G01R29/16 

FIELD: instrumentation.

SUBSTANCE: proposed transducer comprises the following main components: reverse sequence voltage filter, first and second differentiating inductive current inverters with their coils inductively coupled with current conductors of three-phase three-wire circuit and low-pass filter. Said reverse sequence voltage filter with output clips is composed of RC circuit including capacitors and trimmer resistors. Said filter is tuned so that in measurement of sine currents of direct sequence the voltage between said clips in steady state equals zero. Low-pass filter has complex-conjugated bands while peak of filter skirt corresponds to the source rated frequency. Filter suppresses higher harmonics to make said voltage between said clips in steady state, in fact, proportional to revere sequence current first harmonic.

EFFECT: higher selectivity and sensitivity of transducer at high content of higher harmonics.

2 cl, 5 dwg, 3 tbl