A comparative study on the effect of electrical ageing on electrical properties of palm fatty acid ester (PFAE) and FR3 as dielectric materials

Transformer oil is commonly used in electrical insulation, cooling and lubrication of sliding components. There are many factors that negatively affect the electrical insulation properties of power transformers in its operation. Due to the increasing need to replace the petroleum-based mineral oil, there is an interest in replacing the oil with biodegradable vegetative-based oil. The properties of alternative oils that can be used to replace the existing mineral oil are described. Firstly, the vegetable oil was analyzed using computational simulation to investigate the dielectric characteristic and compared to the existing mineral oil. Then, a comparative experimental study concerning the ageing of vegetative-based oil, namely palm fatty acid ester (PFAE) and FR3 by comparing them with the commercially available mineral oil was conducted. Several important properties such as breakdown voltage, the dielectric dissipation factor (tan d) and the capacitance of PFAE and FR3 oils have been measured. Varying ageing time have been applied during experimental process. Based on the experimental results, both oils show higher breakdown voltage compared to the mineral oil. In addition, both of the vegetative-based oils have lower value of dielectric dissipation factor and higher value of capacitance. Therefore, both oils are good insulating oils for transformer applications.