基于Teflon AF/陶瓷复合膜和电化学传感器的变压器油中溶解气体的在线监测系统

设计并制成了测定变压器油中3种故障气体(氢气、一氧化碳和乙烯)的在线监测系统。采用Teflon AF/陶瓷复合膜作为油气分离的组件;采用RAE Systems的氢气电化学传感器、一氧化碳电化学传感器和乙烯电化学传感器。试验表明,采用上述复合膜组件可以在4h内实现油气平衡。为克服温度变化对电化学传感器响应信号的影响,采用温度控制模块使测定单元处于30℃的恒温环境中,保持恒温条件不仅使电化学传感器响应信号不受干扰,而且可延长电化学传感器的使用寿命。气体组分之间的交叉干扰采用信号矩阵算法予以解决,运用所提出的监测系统,上述3种气体的相对测定误差均在15%以内,测定值的相对标准偏差(n=5)为7.3%(氢气),3.9%(一氧化碳),2.1%(乙烯)。

On-Line Monitoring System for Dissolved Gases in Transformer Oil Using Teflon AF/Ceramic Composite Membrane and Electrochemical Sensors

An on-line monitoring system for 3 trouble gases(H2,CO and C2H4) in transformer oil was designed and fabricated.Teflon AF/ceramic composite membrane was used in the system as a module for separation of the gases from oil,and electrochemical sensors of the RAE systems for H2,CO and C2H4 were used.It was shown that the equilibrium between oil and gas was attained within 4 h by using the composite membrane.A constant temperature enviroment at 30℃ was maintained in determination units by using a thermostat,to eliminate the interference of temperature fluctuations to the response signals of the electrochemical sensors.The temperature control not only could keep the response signals of the electrochemical sensors away from the interference,but also keep longer service life of the electrochemical sensors.The problem of cross-interference between the gases was solved by the matrix calculation of the signal values.As shown by the results given by the monitoring system,the relative errors of determined results of the 3 gases were kept within 15%,and values of RSDs(n=5) found were 7.3% for H2,3.9% for CO and 2.1% for C2H4.