基于恒温真空溅射循环脱气测定高压电力变压器绝缘油中9种溶解气体方法

Determination of 9 Kinds of Dissolved Gases in Insulating Oil of High-Voltage Power Transformer Based on Thermostatic Vacuum Sputtering Cycle Degassing

为准确高效地测定绝缘油中特征气体的含量和变化率,引入全密封恒压采样和智能控制恒温真空溅射循环脱气样品前处理方法,采用并联双毛细管柱、FID和TCD三检测器和镍转化炉色谱系统,建立了同时测定绝缘油中H_(2)、CH_(4)、C_(2)H_(6)、C_(2)H_(4)、C_(2)H_(2)、CO、CO_(2)、O_(2)、N_(2)9种特征气体的真空溅射循环脱气-气相色谱定量分析方法,优化了脱气平衡温度、时间、真空脱气条件和色谱条件。结果表明,在试验浓度0.01μL/L~1.0 mL/L范围内,9种气体线性关系良好,相关系数(R2)在0.9968~1.0000之间,氢、烃类、CO_(2)和CO气体的检出限分别达2.0μL/L、0.1μL/L、5.0μL/L、5μL/L,定量限达到7μL/L、0.4μL/L、12.5μL/L、12.5μL/L。3个加标水平下9组分混合气体回收率在88.3%~99.2%,相对标准偏差(RSD,n=3)为0.27%~3.41%。该方法过程高效、结果准确可靠、重复性好,解决了油中含气量测定常规方法结果可靠性低、脱气率不稳定、结果与实际从在重大偏离、过程环境安全表现差等问题,可以快速准确地测定绝缘油中9种特征气体的真实含气量。

In order to determine the contents and change rates of characteristic gases in insulating oil efficiently,sample pretreatment method developed by sputtering and cycling degassing under vacuum and constant temperature condition in this work,with airtight and constant pressure sampling,an analytical method based on gas chromatography was developed for the determination of nine dissolved gases in insulate oil,which are H_(2),CH_(4),C_(2)H_(6),C_(2)H_(4),C_(2)H_(2),CO,CO_(2),O_(2),N_(2).The degassing equilibrium temperature,equilibrium time,vacum degassing conditions and chromatographic conditions were optimized.The results show that with the test concentration range of 0.01μLL~1.0 mL/L,nine gases have a good linear relationship,and the correlation coefficient(R2)is 0.9968~1.0000.The detection limit of hydrogen,hydrocarbon,CO and CO_(2) reached 2.0μL/L,0.1μL/L,5.0μL/L and 5.0μL/L respectively,and the limit of quantification reached 7μL/L,0.4μL/L,12.5μL/L and 12.5μL/L respectively.The recovery rate of 9-component mixed gas at 3 spiked levels is 88.3%~99.2%,and the relative standard deviation(RSD,n=3)is 0.27%~3.41%.The method is more efficiency,high accuracy and good repeatability.It solves the problems of low reliability,unstable degassing rate and poor process environmental safety performance of the conventional method.This method can determine the content of 9 characteristic gases in insulate oil efficiently,and provides a necessary basis for the determination of the gas growth rate in insulate oil system accurately.