On-line Direct Clamping Pressure Monitoring of Power Transformer Windings

This paper presents a novel system for measuring the clamping pressure of transformer windings. The clamping pressure is essential for the integrity of a transformer during short circuit events. The introduction of new loading patterns, increased dynamic loading, may accelerate cellulose degradation and reduced clamping pressure. Direct measured clamping pressure and temperatures together with physical models will facilitate condition-based maintenance and digital twins. The paper explains how the sensors work and presents data from a heat run test as well as in-service conditions. It is demonstrated how the clamping pressure changes with the transformer loading and temperature.