Research On Preparation Of Rape-seed Insulating Oil And Its Hydrolysis Dynamic Characteristics

Mineral insulating oil has excellent high coolant capability and electric insulating property and low cost,it has played important roles in oil-immersed high voltage equipment more than a century. But its burning and flash points are too low to satisfy the requirement of fireproofing. At the same time,it is poorly biodegradable and may contaminate soil and resident conditions when serious oil leakage occurs. Therefore research of the environment-friendly vegetable insulating oil with high flash point and high biodegradable percent has become a pop project;Flash point of vegetable insulating oil is higher than 300℃, it is a fire resistant oil;its biodegradable percent is larger than 97%,it will not pollute the water and inhabited area. Nowadays,the output and quality of oil corps are improved by using gene techniques,and the reserves of mineral oil become decreased,so vegetable insulating oil could be the green substitute as mineral oil.In this paper, the domestic and overseas research situation of vegetable insulating oil was summarized and analyzed; explored the methods how to refine the vegetable oil to dielectric liquid;based on the test researching results,the advantage and disadvantage of rape-seed oil for using as insulating oil was also researched. The hydrolysis dynamic of rape-seed insulation oil was systematically studied at different temperatures,reaction times and water-oil ratio,The variation between the hydrolysis degree of insulating oil and reaction temperature was determined using the Arrhenius Empirical equation;and the series dielectric properties of vegetable insulating oil under different hydrolysis degree was tested : AC-breakdown voltage , relative permittivity and dielectric dissipation. This paper is the groundwork of using rape-seed oil as dielectric liquid and filled up the blank of vegetable insulating oil studies in domestic study.The investigation shows,according to the chemical composition and molecular structure of vegetable oil,rape-seed oil high in oleic acid is the best choice as base oil. Controlling the dominating testing conditions in vegetable oil refined processes, and using repeated refined method, the acid value of vegetable oil can be limited under 0.03mgKOH·g-1,the AC-breakdown voltage has reached more than 60kV,and the physical,chemical and electrical properties of vegetable oil met the requirements of standard GB2536-90 .From the experiment data,the electrical properties of refined insulating oil changed regularly under different hydrolysis degree,insulating properties were influenced inordinately. According to the chemical molecular structure and the influence of electric field,the mechanism of the change of electrical properties are analyzed,and they provide experiment basis for the ageing problems of vegetable insulating oil in transformer operation.