【作者】 陈洁；

【导师】 郭团；

【作者基本信息】 暨南大学 ， 光通信与光传感， 2020， 硕士

【摘要】 电力工业作为经济发展的基础产业,其安全稳定至关重要。在电力系统中,输电线路和变压器是两块非常重要的部分。由于长期运行以及自然界不可抗力的作用,输电线缆会由于自身剪切应力的变化导致电缆内部扭曲磨损甚至断裂,电力变压器由于内部铁芯及绕组等配件的故障导致箱体表面异常振动进而严重影响电力系统的安全。为了避免输电线缆和变压器对经济造成的巨大损失,需要发展带电运行状态下的有效监测仪器。光纤传感器以光学信号为传输媒介,可实现对外界被测信息的实时、高灵敏度传感和长距离信号传输。光纤传感器具有抗电磁干扰、绝缘性好、响应速度快、耐腐蚀以及便于多点组网等优点,为现代传感技术的发展提供了新的方向,适合应用于传统电子传感器受限的电力系统。本论文针对电网监测的实际需求,研制了针对输电线路的表面等离子体共振光纤扭转传感器和面向超高变压器的多点光纤振动传感网络与系统构建。(1)面向“空气-液体”双介质的表面等离子体共振光纤扭转传感器一种基于表面等离子体共振(SPR)并能够在气态和液态介质中工作的倾斜光纤光栅扭曲传感器提出并被证明。使用镀金的37.5度倾斜光纤光栅可以产生两个包层模式共振窗口,能够在“空气-液体”双介质环境下进行扭转监测。由于传感器的偏振相关性,在扭转0-90度和90-180度下SPR模式的归一化光强呈现线性响应。结果表明,传感器在空气和液体中工作时,灵敏度分别为1.15%/度和1.22%/度,适用于结构健康监测应用。(2)面向超高压变压器的多点光纤振动传感网络与系统构建在广东云浮卧龙变电站主变500k V三相变压器上成功安装了一套光纤振动传感系统。在A/B/C三相相同位置各分别安装了6个传感器,共计18个传感器来对变压器的健康状况进行实时有效监测。系统中使用的传感器是基于悬臂梁结构,通过相干解调采集到的时频信号分析,对其中的基频100Hz以及基频倍频200Hz、300Hz分量的幅值进行分析,确定正常工作状况下主变压器A/B/C各相的振动强度及频率分量幅值都会在一个正常幅值空间内,长时间运行波动幅度有限。通过监测变压器振动频率分量的幅值,可预测变压器结构健康问题,消除安全隐患。更多还原

【Abstract】 As the basic industry for economic development,the safety and stability of the power industry is closely related to national economic security,people’s daily life and social stability.In the power system,transmission lines and transformers are two very important parts.Due to long-term operation and force majeure in nature.Power transmission cables will wear or even break due to changes in their own shear stress.Power transformers will have abnormal vibrations on the surface of the cabinet due to internal core and winding failures,which will seriously affect the safety of the power system.In order to avoid the huge economic loss caused by transmission cables and transformers,it is necessary to develop effective monitoring instruments.The optical fiber sensor uses optical signals as the transmission medium,which can realize real-time,high-sensitivity sensing and long-distance signal transmission to the external measured information.In addition,the optical fiber sensor has the advantages of anti-electromagnetic interference,good insulation,fast response speed,corrosion resistance and easy multi-point networking.It provides a new direction for the development of modern sensing technology and is suitable to power transmission systems with limited traditional electronic sensors.According to the actual needs of power grid monitoring,this thesis develops a surface plasmon resonance fiber twist sensor for transmission lines and a multi-point fiber vibration sensing network system for ultra-high transformers.(1)Surface plasma resonance optical fiber twist sensor for"air-liquid"dual media measurement.An optical fiber twist sensor based on surface plasmon resonance(SPR)excitation and able to operate both in gaseous and liquid media is proposed and demonstrated.The use of a gold-coated 37.5~°tilted fiber Bragg grating allows to generate two windows of cladding mode resonances,providing surrounding refractive index sensitivity in two different external media.The relative optical power of the SPR mode in each case exhibits a linear response to the twist angle of the fiber from 0~°to 90~°,as well as from 90~°to 180~°,as a consequence of the polarization dependency of these sensors.The results show sensitivities of 1.15%/~°and 1.22%/~°with the sensor working in air and liquids respectively,being suitable for deformation measurement and structural health monitoring applications.(2)Construction of multi-point optical fiber vibration sensing network and system for ultra-high power transformer.A fiber-optic vibration sensing system was successfully installed on the 500k V three-phase transformer of the#2 main transformer in Yunfu Wolong Substation,Guangdong.Six sensors are installed in the same position of the three phases of ABC power transformer,a total of 18sensors are installed to monitor the health of the transformer in real time.The sensors used in the system are based on a cantilever structure.The time-frequency signals collected through coherent demodulation are analyzed,the amplitudes of the 100Hz,200Hz and 300Hz components are analyzed under normal working conditions.The vibration intensity of each phase of A,B,and C three-phase transformers will be in an amplitude space,and the fluctuation amplitude for long-term operation is limited.By monitoring the amplitude of the vibration frequency component of the transformer,health problems of the transformer structure can be predicted.更多还原