Modifying the thermal performance of electrical distribution transformers using phase change materials (paraffin wax)

In this paper, an electrical distribution transformer has been studied experimentally and a novel technique has been proposed to enhance its cooling performance by addition of paraffin wax to transformer oil using closed containers made of aluminum. These containers were immersed in the transformer oil. A 100 kVA transformer was used as a model for study because these transformers are widely used in the electricity distribution network in Iraq. As temperature rises, the phase change material (paraffin wax) absorbs heat and melts inside the containers at a constant temperature. This feature can be utilized to store heat for a period until the temperature for weather drops; then this heat is rejected, and the wax begins to solidify. In this experiment, five containers were used, each containing 2 kg of wax. The results showed a clear decrease in the temperature of the oil, which led to the enhancment of its thermal insulation and kept the oil from failure and the preserved the transformer from breakdown. The results showed that the reduction in temperature is approximately 7 degrees C and the reduction increased upon increasing the amount of wax added.