基于电化学传感器的SF6分解气体检测技术研究

SF_6气体绝缘类电力设备具有体积小、结构紧凑、绝缘性能稳定、运行可靠等优点,被广泛应用于特高压和超高压电力系统中。当电力设备内部发生绝缘故障时,绝缘气体SF_6由于局部放电及局部过热发生分解反应,最终生成数种稳定SF_6分解气体,通过对这些分解气体组分进行定量检测和分析,可反演出设备内的故障或安全隐患。通过搭建电化学传感器响应特性的测试平台,在气体检测罐中模拟SF_6分解气体并进行检测,得到了CO、SO_2和H_2S气体电化学传感器的响应特性。实验结果显示出CO传感器有负的温度特性,SO_2和H_2S电化学传感器具有正的温度特性,并采用二次曲线拟合确定了传感器的温度补偿曲线;同时还发现CO、SO_2和H_2S气体传感器均具有良好的线性特性,但SO_2传感器会对H_2S气体做出响应,通过采用交叉干扰计算,建立传感器信号矩阵算法保证了测量结果的准确度。最后,通过运用多组分混合气体验证了传感器信号矩阵算法具有很高的可靠性和准确度。

Research on SF6 gas decomposition detection method based on electrochemical sensors

SF6 gas insulated electrical equipment has been widely used in the high voltage and extra high voltage power system. The electrical equipment could generate partial discharge and local overheating because of the insulation faults, which further results in SF6 gas decompensating and finally generate several kinds of SF6 decomposition products. The SF6 decomposition products can be quantitatively detected by using relevant electrochemical gas sensors, which contributes to deducing internal faults of the equipment. A testing platform for detecting electrochemical sensors is established. By configuring and detecting SF6 decomposition products in the detection tank, the response characteristics of CO, SO2 and H2S sensors are achieved. Experimental results show that the CO sensor has a negative temperature characteristic, SO2 and H2S sensors have a positive temperature characteristic, and the temperature compensation curves are fitted by using the quadratic fitting method. All sensors exhibit a good linear relationship, but SO2 senor also has a response to H2S gas. The sensor data matrix is used to guarantee the measurement accuracy. In the end, the multi component mixing gas is configured and used to verify the sensor data matrix, and the results show that the sensor data matrix has high reliability and accuracy.