METHOD FOR CHECKING TAP CHANGER FOR FUNCTIONAL CAPABILITIES Russian patent published in 2003 - IPC

FIELD: electrical engineering. SUBSTANCE: method includes measurement of current and voltage RMS values in electric drive motor, determination of torque as function of actual motor output calculated form measured values, and determination of tap changer settings. Then settings and torques are correlated and compared with stored desired values. As an alternative, timenormalized torque variation characteristic is obtained to eliminate differences depending on sense of rotation of drive and this characteristic is divided into time intervals corresponding to different steps of load switching. Time intervals are compared with stored desired values. If comparison of actual and desired values shows that preset threshold value is higher than desired, corresponding warning or drive disconnection signal can be generated. EFFECT: enhanced reliability of tap changer check-up, response to fault occurrence and its elimination. 7 cl, 3 dwg