CONTACTLESS CURRENT SENSOR ON SURFACE ACOUSTIC WAVES Russian patent published in 2022 - IPC G01R19/00 

FIELD: power industry.

SUBSTANCE: invention is aimed at remote monitoring of current or voltage changes in high-voltage overhead power lines, transformer substations and electrical distribution cabinets. The essence of the invention lies in the fact that the two delay lines are oriented perpendicular to each other and fixed on a dielectric substrate in non-magnetic housings. Each delay line has a piezoelectric sound line made of lithium niobate single crystal, receiving-transmitting and reflecting interdigital transducers and a magnetically sensitive film made of FeNi between them along the propagation of the surface acoustic wave. The delay line of the measuring channel is oriented along the direction of the magnetic field strength in the conductor. The distance between the central axes of the interdigital transducers in different channels differs by a quarter of the length of the surface acoustic wave at the central frequency, and the reflected waves come to the receiving and transmitting interdigital transducers in the opposite phase and induce anti-phase voltages in them, which are mutually compensated in the transceiver antenna of the sensor. The meter of the dependence of the total signal from both delay lines when the magnitude of the magnetic field in the conductor changes is made remote and contains a reader and a receiving and transmitting antenna directed at the receiving and transmitting antenna of the sensor.

EFFECT: improvement of measurement accuracy by equalizing changes in the velocities of surface acoustic waves on the measuring and reference delay lines when the ambient temperature changes, as well as simplification of sensor maintenance due to remote indication of measurement results.

5 cl, 7 dwg