Undoubtedly, the main and most important task of transformers is to convert electrical energy into voltage levels. Transformers allow the adjustment of voltage levels. For this reason, transformer tests and maintenance should be carried out frequently. These tests and maintenance should be performed taking precautions against any possible danger. The grounding process of the points in transformers, called stars, should be carried out before performing any test or maintenance. Before starting the test and maintenance, the electricity from the network feeding the transformer should be disconnected. All lines should be individually checked with the pen used for high voltage testing. Grounding should be applied to high and low voltage points in transformers due to the generators in them. Tests should be conducted to ensure the oil inside the transformer performs its duty. The main purpose of performing transformer tests and maintenance is to ensure that energy is delivered correctly. When testing the transformer, the insulation of the cables should be checked to make sure they are sufficient. A test called TTR is performed. TTR test measures the capacity of the transformer to convert high and low voltage. Another test especially conducted for transformers is the grounding test. The grounding test checks whether there is enough protection or not.
When performing transformer tests and maintenance, cable connections are checked with thermal cameras. The amount of oil in the transformer is measured. It is checked whether the oil inside the transformer is sufficient or not. To ensure that the transformer has a long service life, it should be checked if there is any leakage in the oil. When performing transformer tests and maintenance, the loosening bolts which may occur seasonally in the transformer are detected and tightened. Cables through which high voltage passes are checked and repaired. Low voltage cables passing through high voltage cables are also tested. Inner maintenance is important as well as external maintenance during transformer tests and maintenance. Walls can be washed with water for external maintenance. The adequacy of grounding in the star points, which is an important point in transformers, is checked. As cables inside the transformer cannot be washed with water, they are cleaned with thinner. The functionality of the cooling system, which is present in most transformers, is checked. Additionally, cables cleaned with thinner should be dried very well.