TEMPERATURE RISE ANALYSIS IN SYNTHETIC ESTER OIL IN 20 0.4 KV DISTRIBUTION TRANSFORMERS OF 2500 KVA

Currently, all electrical systems from the distribution system require the use of transformers, which are equipped with environmentally friendly transformer oil. A Transformer is an electrical equipment that is used to increase and decrease voltage in alternating current (AC) systems, both single phase and three phase. This equipment is made up of several main components such as iron cores, windings and cooling fluid. Transformer oil itself functions as a coolant for the primary secondary winding and as insulation between windings. However, as the load increases and the transformer ages, the temperature and performance of the transformer oil tend to decrease. In addition to the two primary and secondary windings in a transformer, there is also a liquid inside that functions as a coolant and insulator, namely transformer oil of the synthetic ester type.This oil actively protects the transformer from overheating caused by current flow in the windi ngs and iron core. The aim of this research is to test the highest oil temperature rise or the terms top-liquid temperature and top-liquid temperature rise in a distribution transformer with a scheme based on the IEC 60076-2-2011 standard, which is tested by means of current injection on the primary side while the secondary side is connected short. The results obtained indicate that the steady-state top-liquid temperature is 83.2°C and the top-liquid temperature rise is 54.47°C. This shows that the application of this type of transformer oil can effectively dissipate heat in a transformer, which in turn will contribute to increasing the transformer's lifespan and be environmentally friendly.