The transformers are the most valuable part of the electricity distribution system. The initial price of the middle or low voltage transformer is few million HUF, but price level of the high voltage transformer can easily reach up even the billion HUF. Not only the value of transformers but also the security of supply is important that the operators of the power stations and transmission networks should receive sequential information regarding the actual condition of the facilities, needed repairs and replacement of the units in extreme cases. It shall be assisted by the diagnostics of the transformers, which could forecast and detects the failures with different type of diagnostic tests. Many diagnostic tests are available to check and analyze the condition of the transformers, thereby different type of failures are detectable.
The Transformer Status Indicator (TSI) summarizes the results of diagnostic tests and describes in details the condition of the facility. I expound the diagnostic methods which were used in the departmental XÁT software and also in the applied diagnostic protocols furthermore I present the detectable errors and the calculation of Status Indicator in the theoretical summary of my thesis.
In the second half of my thesis I present the calculation methods of the Status Indicators of three operating transformers (A, B, C), also the calculated results of the diagnostic data, then undertake a comparison of the results of the departmental developed XÁT software. I compare the results obtained, the differences of the methods are clearly detectable. The main aspect of both methods to evince the status of improvement or deterioration of the Status Indicator.