基于NDIR技术的高压组合电器中CF4气体检测方法研究

为了实现对高压组合电器GIS气室中CF4气体的在线实时检测,完善基于气体化学成分分析实现对高压电气设备缺陷诊断,应用非分散红外(NDIR)技术设计了一种光学CF4气体传感器。系统采用单光束双波长结构,确定了折返光路气室类型,提高系统灵敏度。硬件方面,采用具有多路12位精度的模数转换器高性能单片机,进一步提高检测精度。多组分配气系统实验测试结果显示:不同体积分数的CF4气体在RBF?PSO算法温度补偿前后传感器测试的最大示值误差分别为7.93%、1.20%;对不同体积分数的CF4气体量程标定测试时的参比信号幅值与测量通道信号幅值的比值SB/SA进行指数拟合,非线性相关度R2为0.9993;传感器重复性平行实验显示RSD分别为0.87%、0.44%、0.32%。综上,验证了该CF4传感器在测量范围、抗干扰能力、检测精度及重复性等方面的优势。

Research on CF_4 Gas Detection Method in GIS Gas Chamber Based on NDIR Technology

In order to realize the on-line real-time detection of CF4 gas in GIS gas chamber and perfect the defect diagnosis of high-voltage electrical equipment based on gas chemical composition analysis,the optical CF4 gas sensor is designed by applying non-dispersive infrared(NDIR)technology.The system adopts a single-beam dual-wavelength structure to determine the type of return light path gas chamber and improve the sensitivity of the system.In terms of hardware,the high performance single chip microcomputer with multi-channel 12-bit ADC are adopted to further improve the detection accuracy.The test results of multi-group distribution gas system show that the maximum indication error of sensor test of CF4 gas with different volume fraction before and after temperature compensation by RBF-PSO algorithm is 7.93%and 1.20%,respectively.The ratio of SB/SA between reference signal amplitude and measurement channel signal amplitude in the calibration test of CF4 gas range with different volume fraction is fitted exponentially,and the nonlinear correlation R^2 is 0.999 3.The RSD of the sensor is 0.87%,0.44%and 0.32%,respectively.In conclusion,the advantages of CF4 sensor in measuring range,anti-interference ability,detection accuracy and repeatability are verified.