绝缘子污秽在线监测能有效跟踪绝缘子污秽变化，防止污闪事故发生。现有技术存在易受电磁干扰影响、需要现场电源、精度低、可靠性差等缺点。本课题拟采用聚酰亚胺光纤布喇格光栅（PI-FBG）湿度敏感特性进行盐分的测量，解决现有技术存在的问题。本课题将利用高分子聚合物增强聚酰亚胺分子与FBG 的结合力，获得高感湿PI-FBG 的制备工艺。采用傅立叶红外光谱仪研究盐分溶水后对聚酰亚胺与水分子间氢键的化学抑制作用，使用SEM 和TEM 观察盐分对聚酰亚胺表面物理形貌的影响，从物理和化学角度探索盐分对聚酰亚胺吸水膨胀的抑制机理，获得盐分减小聚酰亚胺膨胀应变进而降低FBG 布喇格波长变化量的抑制规律。之后，基于绝缘子人工污秽试验结果，创建利用FBG传感器阵列评估绝缘子上盐密分布和整体盐密程度的体系和方法，解决PI-FBG 对温度、湿度和盐密交叉敏感问题，为建立全光网远程分布式盐密监测系统奠定基础。

On-line monitoring of insulator contamination can effectively track changes in insulator contamination, alarming the occurrence of pollution flashover. Conventional technology has several disadvantages: sensitive to electromagnetic interference, require on-site power, low accuracy and poor reliability. In order to solve these problems, a polyimide fiber Bragg grating (PI-FBG) is proposed to measure the salt based on its humidity-sensitive characteristics. High polymer will be used to reinforce the binding force between the polyimide molecule and the FBG, furthermore improve the humidity sensitivity of PI-FBG. Fourier transform infrared spectroscopy study will be carried out to investigate the chemical inhibition of salt dissolved in water on the hydrogen bonds between the polyimide and the water molecules. The physical morphology of the polyimide surface will be observed by SEM and TEM to explore the influence of the salt. With these efforts, the inhibition mechanisms of PI-FBG wavelength shift by the salt will be indicated. After that, the insulator artificial pollution tests will be carried out in our laboratory and a salt calculate algorithm, whose parameters are wavelength shift, will be proposed based on the experiment results.