BEHAVIOUR OF POWER TRANSFORMER UHV-LEAD EXIT SYSTEMS UNDER MECHANICAL VIBRATION STRESS AS OCCURRING DURING TRANSPORTATION

Summary

High voltage apparatuses are stressed mechanically mainly while being transported and during earthquakes. To prove withstand capability against transport conditions, mechanical vibration tests are applied in specialized laboratories with shaking (or vibration) tables to assess critical components. The specifications of such test procedures consist of random vibration tests (e.g. transport with truck, railway) and of shock/impulse tests (e.g. handling with fork-lift). This paper describes such a test which was performed with a real ultra-high-voltage transformer lead exit system, presents results and proposes consequences on manufacturing and transportation of transformer lead exits. Caution has not only to be taken by designing transformer lead exit systems with respect to transportation stress, but also for the packaging and handling of the components before the delivery. An attempt has been made to interpret results of transportation tests in terms of seismic withstand capability of a transformer lead exit. This is however a complex question, not easy to answer, because of mainly two unknown factors: the influence of the transformer oil and the shift of resonance frequencies of the lead exit system when being built-in into the transformer tank. In addition to the laboratory tests, vibrations were recorded with a data logger, mounted on a transformer lead exit being transported by truck.

Additional informations

Authors

KALENDERLI OZCAN, Boesch Michael, Guðjónsdóttir, Wohlwend Thomas, Sutter Marcel