IMPROVING THE RELIABILITY OF POWER TRANSFORMERS OLTC DEVICES

Abstract

It is established that one of the effective ways to improve the reliability of the power transformer as a whole is to increase the reliability of its on-load tap-changer (OLTC). As a result of the analysis of statistical material obtained under real operating conditions (the number of transformers is 1000 pieces, the observation period is 4 years), the failure statistics of its individual elements are given. It is shown that the most not reliable elements of the OLTC are the drive and the contactor. To improve the reliability of the OLTC, the possibility of its development on the basis of an engine with a rolling rotor is considered. A critical analysis of modern OLTC and the proposed technical solution is carried out. The technical and economic feasibility of developing and implementing a new device has been established. On the basis of the general theory of the electromagnetic field, a technique and an algorithm for calculating new sizes of an engine with a rolling rotor for OLTC of power transformers has been developed. The analysis of operational reliability of OLTC based on statistical materials is carried out; the main reliability indices of its elements are calculated. It is established that the introduction of a new technical solution will increase the reliability of the OLTC by 25% and the power transformer by 2-4%. The perspective of the development of a new OLTC device is presented.