Diagnostyka transformatorów energetycznych z wykorzystaniem metody wibroakustycznej

Tematyka artykułu dotyczy diagnostyki rdzeni transformatorów elektro-energetycznych dużej mocy z wykorzystaniem pomiarów drgań wibroaku-stycznych. W artykule, na podstawie analizy drgań mechanicznych kadzi, dokonano oceny stanu technicznego czterech transformatorów blokowych typu TFBb 240000/400. Scharakteryzowano układ pomiarowy, który został wykorzystany podczas rejestracji sygnałów pochodzących od przenoszonych przez kadź drgań rdzenia poszczególnych jednostek. W oparciu o przyjęte w artykule wartości kryterialne podjęto próbę oceny stanu technicznego diagnozowanych urządzeń elektroenergetycznych.

During its operation a power transformer is subjected to the influence of numerous unfavourable factors which shorten its operation time and can cause unexpected disastrous failures. As far as the active part of a transformer is considered, magnetostrictic vibrations and cellulose depolymerization are the most harmful factors causing the loss of mechanical strength. Their influence results in the gradual loosening of the pressing and clamping of the core and transformer windings, which leads to the weakening of the active part mechanical construction (Fig. 1). In the electric power sector there are a few methods for detection of damages in power transformers. One of them is the vibroacoustic method which consists in measurement and analysis of vibrations of the object under study. Its application to high-power transformer diagnostics enables, first of all, assessing the technical condition of the core. Additionally, combining this method with other diagnostic methods can provide information not only on the core technical condition but also on the solid insulation properties of the device being tested [5 - 6]. In the paper the technical assessment of the condition of four unit transformers of type TFBb 240000/400 is performed basing on the analysis of mechanical vibrations of the tub. The basic technical parameters of the transformers are listed in Table 1. The measuring system used for recording the signals coming from the core vibrations of the particular units and transferred by the tub is described. Based on the criterion values [among others 6 - 8] an attempt to assess the technical condition of the electric power appliances diagnosed is made. The investigations and analyses carried out confirm that the measurement results of vibrations of the particular units have not revealed any damage to their cores or other defects of mechanical character.