Experimental Study Of Electricity Performance Of De-ionized Water/Ethylene Glycol Mixtures

As both insulator and energy storage media, de-ionized water combines the advantages of high relative permittivity(is about 80), self repairability, low cost and ease of handling. However, the application of it is restricted because it will freeze in low temperature. To expand the application of it, it's very exigent to solve this problem. It's fortunate that the freezing point of water can be decreased when the ethylene glycol is added. The changing of the freezing point was studied when the ethylene glycol was added, and the electricity performance of water/ethylene glycol mixtures was also researched in this paper.Firstly, the electricity performance of de-ionized water was studied by using coxial transmission line as experimental equipment. It's showed that the relative permittivity is about 80, the resistance ratio is 12.58M Ω · cm, the average breakdown strength is 112.18kV/cm when the average breakdown time is 5.77μs in normal temperature. It proves that water is good at electricity performance.Secondly, the electricity performance of de-ionized water/ ethylene glycol mixtures was studied. It's showed that the average breakdown strength and the resistance ratio are improved obviously while the relative permittivity of the mixtures' is decreased a little in normal temperature. At the same time, the average breakdown time is prolonged. For example, the relative permittivity of the mixture of 59.0% is 71.26, which is decreased 10.93% when compared to the water's; the resistance ratio is 35.71M Ω· cm, which is improved 2 times. The average breakdown strength is 142.81kV/cm when the average breakdown time is 7.31μs, which is improved 35.20% when compared to the water's. Seen from the experiments, the average breakdown strength and the resistance ratio are increased while the ralative permittivity is decreased when the concentration is improved.Finally, the freezing point of de-ionized water/ ethylene glycol mixtures and the electricity performance of them were studied in low temperature. It's showed that the relative permittivity and the resistance ratio are increased when the temperature is decreased. Furthermore, the freezing point of the mixture is decreased when the concentration is improved. For example, the freezing point of the mixture of 59.0% is -39℃.