One of the most important and most expensive devices of an electrical substation are transformers. It is quite important to know some of its details and using them to be sure about its good condition. In case we know these details we can decide if we should maintain it or not, because these maintenance works are complicated and they can carry especially high expenses. In case we made our decision well we can save the transformer or avoid disastrous failures.
The diagnostics of high-voltage transformers have reached the level of online-monitoring nowadays. The previous works are done by sensors and computers, and the diagnostic works go on through the whole operation of transformers.
My project is about to show detailed the online - monitoring systems, and sensors, and to find the answer on the following question: Can we use online monitoring on 120/10-20 kV, and 20/0.4 kV transformers? What is the reason that we do not use online monitoring on lower voltages? To answer these questions I will present some real plans and expenses of the electrical company of Hungary ELMŰ to demonstrate the economical background of these works