| CPC G01R 19/2513 (2013.01) [G01R 15/16 (2013.01); G01R 15/04 (2013.01)] | 20 Claims |
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1. A system for compensating for drift in a switch gear voltage sensor, the system comprising:
a circuit including a compensation capacitor and a voltage divider including a measurement resistor and a divider resistor, the compensation capacitor being in parallel with the voltage divider, the circuit configured to
receive, at the measurement resistor, a first signal (Input 1) from a first capacitor of the voltage sensor (C1_2) formed by an electrode and an inner electrically conductive sheet of the switch gear voltage sensor,
receive, at the compensation capacitor, a second signal (Input 2) from a second capacitor of the voltage sensor (C1_1) formed by the electrode and the inner electrically conductive sheet of the switch gear voltage sensor, the second capacitor being in parallel to the first capacitor,
generate a third signal (V1) at an output of the measurement resistor based on the first signal, and
generate a fourth signal (V2) at an input of the compensation capacitor based on the second signal;
an electronic processor configured to
receive the third signal and the fourth signal,
determine an angular frequency of the third signal (V1),
determine a phase difference between the third signal (V1) and the fourth signal (V2),
determine a resistance value based on the angular frequency and the phase difference,
determine a capacitor voltage across the compensation capacitor,
determine an initial gain based on a line voltage, a capacitance of the second capacitor, a capacitance of the compensation capacitor, and the capacitor voltage,
determine a final gain based on the resistance value, the angular frequency, and the phase difference, and
determine a drift value of the fourth signal based on the final gain.
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