| 摘要 |
PCT No. PCT/SE97/00402 Sec. 371 Date Nov. 12, 1998 Sec. 102(e) Date Nov. 12, 1998 PCT Filed Mar. 10, 1997 PCT Pub. No. WO97/34161 PCT Pub. Date Sep. 18, 1997A method for monitoring an on-load tap changer wherein the recording of sound and its conversion into a sound signal are initiated at the beginning of a connection operation of the tap changer and the sound signal is rectified, converted into a signal envelope, sampled digitally and continuously evaluated with respect to the condition of the tap changer by comparing the envelope with at least one fixed or one continuously updated reference envelope. The comparison is carried out selectively by calculating a dimensionless comparison figure Ti which is based on a quantity measure and a variation measure. |
