Use of Routine Low-Temperature Viscosity Measurement to Prevent Sudden Transformer Failure Upon Very Cold Startup

摘要

When a power transformer is called into service, it may face a high current load. During cold storage, the oil that cools it can congeal. If such a blockage prevents normal oil circulation, the transformer can overheat in its first few minutes of such cold-start operation. When this scenario was first an operational concern for utilities, there was no good test to determine whether oil of concern could lead to this problem. This adaptation of an ASTM test was devised and put to daily use at Manitoba. It has been used for over 25 years to ensure that no batch of oil used here can lead to such an equipment failure.