The compatibility tests between vegetable insulating oil and mineral insulating oil

Vegetable insulating oil shows good performance in electric, high anti-aging ability and environmental protection. Thus it is considered as a promising substitute for mineral insulating oil. In order to the wide spread application of vegetable oil in large power transformers, this paper designed the compatibility tests between vegetable insulating oil and mineral insulating oil. The changing rules of thermal aging characteristics in insulating oil influenced by different proportions were obtained. The changing rules of acid value, moisture content and breakdown voltages of mixed oil influenced by different proportions were analyzed. Experimental results indicate that the molecular composition of insulating oil have a great influence on the physical, chemical and electrical properties of oil. The more of vegetable insulating oil in mixed insulating oil, the higher acid value and moisture content of oil is. Vegetable insulating oil and mineral insulating oil has good compatibility in thermal aging tests.