Patent ID: 6100674
Filing Date: 2000-08-08
Classification: H01H

Abstract:
A method of monitoring operation of a tap changer for a power transformer, comprising the steps of:(a) obtaining measured values at short intervals from one another representing actual conditions of a tap changer during a tap changing operation;(b) detecting positions of the tap changer during said tap changing operation and associating respective ones of said measured values with respective ones of the detected positions;(c) subdividing a range of detected positions or a corresponding time range (t.sub.0 -t.sub.7) into a succession of partial ranges (t.sub.0 -t.sub.1, t.sub.1-t.sub.2, . . . , t.sub.6 -t.sub.7) in accordance with a subdivision function during said tap changing operation;(d) within each of said partial ranges (t.sub.0 -t.sub.1, t.sub.1 -t.sub.2, . . . , t.sub.6 -t.sub.7), determining a characteristic value (m1-m7) of the measured value based upon a predetermined set of calculation rules;(e) comparing the characteristic values (m1-m7) with parameter data stored in nonvolatile memory and classifying the characteristic values in selected classification categories (00H-0DH) based upon the classification; and(f) further processing only these classification categories and generating respective category dependent signals therewith.