Partial discharge on-line monitoring for HV cable systems using electro-optic modulators

A technique for the remote inspection and monitoring of partial discharge (PD) activity using an optical network is described. The network uses a LiNbO/sub 3/, modulator to modulate the intensity of the transmitted laser light approximately proportional to the voltage applied across the modulator. The laser light is transmitted along an optical fibre and measured remotely by a high-speed optical receiver. A capacitive coupler has been used to detect partial discharge activity and act as the modulator's input voltage source. The electro-optic modulator is passive and does not require a power supply at the site of the PD detection sensor. The system has the additional advantages of being immune to electromagnetic interference, having very little signal transmission attenuation, with good sensitivity, compact size, as well as being convenient to use and safe. Both simulation experiments and practical PD tests on two cable systems have indicated that the optical system provides a feasible remote PD monitoring technique for high voltage cable systems.     

10kV中压复合电缆和中间接头的结构及性能

介绍了光纤复合电缆的结构及性能,把具有特定功能的传感光纤和通信光纤嵌入到电力电缆中,构成具有通信和传感功能的10kV中压复合电力电缆,可以实现对输变电网设备、设施状态的在线监测和数据通信传输功能;阐述了针对此光纤复合电缆开发的直通式中压光纤复合电缆接头结构及性能。     

500 kV充油海底电缆导体温度分布式光纤传感监测及应用

依据海南联网系统500 kV海底电缆捆绑特殊海底光缆的实际情况,通过分布式光纤传感技术结合经有限元仿真模型优化的IEC60287热路模型的方法可以监测海底电缆内部的温度分布。在实验室中搭建岸上模拟实验平台,利用中压电缆捆绑光纤的结构进行捆绑电缆岸上模拟实验。同时,将经验证的温度监测方法应用于海南联网系统500 kV海底电缆,以C相空气段为例监测捆绑电缆光单元的温度。采用有限元仿真计算电缆表面的温度,根据电缆表面的温度基于热路模型推导出对应的导体温度,得到电缆导体在实际运行过程中的温度变化。岸上模拟实验测量的导体温度与数值计算得到导体温度的误差低于1.77%, 验证了海底电缆导体温度监测方法的准确性。     

高压直流海缆综合在线监测系统研究

直流海底电缆在我国的应用尚处于起步阶段,运行经验不足,同时由于海底环境复杂,例行巡检困难,因此亟需对直流海缆的在线监测方法进行研究。分布式光纤技术是近年来发展的新型光纤传感技术,可实现对温度、应力等参量的在线测量。文章建立了基于分布式光纤传感技术的高压直流海底电缆综合在线监测系统,综合利用了分布式光纤的BOTDA,ROTDR以及Φ-OTDR原理,提出了布里渊频移解耦方案,可对直流海缆运行过程中的温度、应变、扰动等进行实时测量,同时该系统还融合了船舶AIS功能,实现对直流海缆区域内来往船只的监测及警告,保障了直流海缆的安全稳定运行。最后对该系统在南澳±160 k V直流海缆工程中的运行数据进行分析,验证了系统的有效性。     

110kV光电复合海缆立体在线监测系统研发

通过对分布式光纤传感技术及布里渊光时域反射领域国内外研究应用情况的介绍,阐述了利用光电复合海缆富余光纤作为传感元件进行海缆在线监测研究的技术路线。着重论述分布式光纤温度和应变传感技术原理及基于BOTDR海缆本体状态实时在线监测的研究：船舶自动识别系统（AIS）和视频系统构建的肇事船只确认子系统可以与BOTDR系统联动,提前预警海缆异常状态,确认肇事船只;探讨海洋磁力计对海缆故障点进行水下定位方法。文章归纳总结了从海缆本体状态监测到海上肇事船只确认及海缆故障点定位的海缆立体监测研发成果,该成果在海洋环境下有着广泛的推广应用前景。     

基于虚拟仪器平台的新型分布式光纤传感系统

提出一种可用于探测并定位微弱振动的基于LABVIEW平台的相位敏感光时域反射型(Φ-OTDR)分布式光纤传感系统。该系统中,窄线宽(3.6kHz)、低频率漂移(1MHz/min)的光纤激光器输出的连续光经电光调制器调制成脉冲光,经环行器后从传感光纤的一端输入,并在环形器的另一端通过光电探测器检测传感光纤中的后向瑞利散射光,探测器接收到的信号经过放大后采集到上位机中,使用LABVIEW进行数据处理。当在传感光缆表面或附近有压力或振动导致光纤中瑞利散射光相位发生变化时,由于干涉作用,光相位变化将引起光强度的变化,经过适当的数据处理后可得到压力或振动点的位置。这种传感系统可应用于周界安防、石油管道安全监测、大型结构监测等。     

110kV光纤复合电缆接头制作工艺研究

阐述了传统110 kV电缆、光纤及带光纤复合电缆中间接头安装技术;以实验室测试和现场安装为依据,探讨了110 kV光纤复合电缆中间接头的制作工艺,对其中关键工艺提出了多种解决方案,并总结出了较为合理的实施方法。     

高压电缆温度在线监测系统中热点位置研究

基于光纤的分布式温度测量系统是一种利用激光在光纤中的传播特性,实现实时测量空间温度场的技术。文章介绍了用于高压电缆表面温度测量的光纤测温系统,建立了高压电缆的热路模型,分析了不同位置表面温度对电缆线芯温度计算结果的影响,给出了不同排列方式下光纤安装位置的指导性意见。     

Development of long range optical fiber sensors for compositesubmarine power cable maintenance

Long range optical fiber sensors for power cable maintenance have been incorporated into a newly developed 500 kV DC submarine power cable. Optical fibers are used for a distributed temperature sensor and a mechanical damage sensor. The distributed temperature sensor provides data on temperature at distances up to 30 km, and the mechanical damage sensor locates external damage points on the submarine cable. After each characteristic was investigated, optical fiber sensors were incorporated on the submarine power cable. This composite cable was evaluated by various mechanical tests. The results were satisfactory and showed the composite cable to be of practical use. This new approach of incorporating optical fiber sensors in the cable structure brings a new sophistication and reliability to cable maintenance     

光纤光栅传感器在电力电缆测温系统中的应用

温度监测是预防电力电缆大量使用引发事故的常规方法,通过对国内外4种常用电力电缆测温技术的分析,认为光纤光栅温度传感技术抗电磁干扰能力强,布置灵活,可实现多目标温度的快速准确测量;阐述了光纤光栅传感器的测温原理;实际应用表明,利用光纤光栅传感器监测电力电缆温度安全可靠、精度高、监测距离远.     

Performance analysis of a time-division-multiplexed fiber Bragggrating sensor array by use of a tunable laser source

The results of an investigation of the performance of a time-division-multiplexed (TDM) fiber Bragg grating (FBG) sensor array using a tunable laser source are reported. The system performance is found limited by the extinction ratio of the optical pulse modulator used for pulse amplitude modulation. Formulas that relate the crosstalk to the extinction ratio of the optical pulse modulator, the modulation parameters of the tunable laser, and the optical path differences among sensing channels are derived. Computer simulation shows that an array of 20 FBG sensors with 3 με resolution can be realized with a commercially available single Mach-Zehnder type optical pulse modulator of -35-dB extinction ratio     

厦门220kV春围Ⅱ路海底电缆工程概述

厦门220 kV春围Ⅱ路海底电缆首次在国内使用了大截面(2 500 mm2)、高电压(220 kV)等级的自容式充油聚丙烯薄膜木纤维复合纸(PPLP)绝缘复合光纤电缆.介绍了该海底电缆的选型思路、电缆结构以及用于海底电缆敷设的自行设计的退扭系统,对海底电缆光纤测温、油压监测、海域视频监视等辅助系统进行了阐述.     

Conductor temperature monitoring system in underground powertransmission XLPE cable joints

A conductor temperature monitoring system using the current method was developed to estimate conductor temperatures at joints of extra-high-voltage (EHV) underground power transmission XLPE cables in real time. The validity of the software and hardware was confirmed by measurements on an extrusion molded joint (EMJ) of a 275 kV 1×2500 mm² aluminum-sheathed XLPE cable. The mean circumferential jacket surface temperature over the EMJ, where the cross section was larger than that at the cable portion, was measured by a line thermosensor using thermocouples or a distributed temperature sensor using an optical fiber. The conductor temperature in the cable joint was estimated by numerically solving simultaneous differential equations with 31 unknowns. A system which allows measurement of the cable conductor current at insulation joints of installed lines was also developed     

Narrow linewidth, tunable Tm3+-doped fluoride fiberlaser for optical-based hydrocarbon gas sensing

Operation of an efficient continuous-wave (CW) thulium-doped fiber laser emitting at wavelength, λ=2.31 μm is reported. The fiber laser parameters are optimized with a view to ultimately producing a compact and efficient laser source for optical absorption based gas sensing. A number of fiber laser configurations are investigated to assess their suitability for narrow linewidth, tunable fiber laser operation emitting around λ=2.3 μm, which is a wavelength region of significant importance for hydrocarbon gas monitoring. Tuning ranges of 140 nm and linewidths of less than 210 MHz have been demonstrated with lasers with bulk external tuning grating. Preliminary hydrocarbon gas sensing investigation confirm the potential of this source for detection of ppb gas concentrations     

Fiber-optic tactile microsensor for detecting the position of thetip of a fiberscope

A tactile microsensor employing optical fibers has been developed and evaluated. The sensor is used for touch sensing to detect the position of the tip of a fiberscope inside a small tubule, such as a blood vessel. The sensor consists of bosses as feelers, which are split sections of the end of a polyurethane tube, a metal diaphragm as a mirror and optical fibers transmit light. The sensors are fabricated using silicon micromachining, such as anisotropic etching and excimer laser etching. The sensing principle is based on the detection of changes in optical reflective intensity from a diaphragm located between a boss and an optical fiber. The width and height of the boss are both 200 μm. For the transmitting source and signal light, a multimode optical fiber 50/125 μm (core/clad) in diameter is used. The results show that tactility measurements can be made easily and safely in blood vessels. This paper describes the structure, fabrication processes, and performance of the sensor. We also propose micromeasuring systems combined with the tactile sensor and a fiberscope of contact type     

光纤温度传感器在电力电缆监测中的应用

文章分析了电力电缆运行过程中温度升高的原因,简单介绍了基于光纤光栅、拉曼散射和布里渊散射的光纤传感技术的温度测量原理.针对电力电缆温度监测的现状,探讨了3类光纤传感器在电力电缆监测中的应用模式,在对3类传感器在电力电缆温度监测时的特点、性能进行比较的基础上,介绍了基于布里渊传感的海底电缆在线监测案例.随着智能电网的发展,光纤传感器尤其是基于布里渊散射的传感器将在电力电缆监测中发挥重要作用.     

应用于高压电缆的光纤分布式温度传感新技术

光纤分布式测温技术是一种利用激光在光纤中的传播特性,实现实时测量空间温度场分布的新技术。它能对光纤沿线的温度场进行分布式的连续检测。本文介绍了该技术的测温原理,以及其在高压输电电缆内部温度监测方面的应用,并介绍了光纤安装方式对测温精度的影响。     

Sagnac式光纤电流互感器的光波偏振特性建模及误差特性分析

Sagnac式光纤电流互感器要求光波具有特定的偏振特性。起偏器、波片、保偏光纤主轴熔接等因素均会引起光波偏振误差,非理想的偏振光波导致互感器干涉信号串扰。围绕Sagnac式光纤电流互感器偏振误差特性,采用琼斯矩阵建立光纤电流互感器光波偏振模型,分析光纤电流互感器中线偏振态及圆偏振态演变过程;以光纤电流互感器光波偏振模型为基础,研究光波偏振器消光比、保偏光纤主轴熔接角以及波片相位延迟角对光纤电流互感器光波偏振及性能的影响。     

电力电缆及其接头运行温度监测技术研究

分别阐述电力电缆以及电缆接头使用的多种运行温度监测技术,包括点式温度监测、光纤温度监测和红外温度监测等.介绍了每种运行温度监测技术的工作原理、优缺点以及这些运行温度监测技术的适用场合,同时也对某些运行温度监测技术在实际中的具体实现和实际使用效果进行了说明.     

无线通信在高压配电线路电能计量装置的应用

目前10 k V高压电能表主要采用光纤或无线通信传输数据,光纤硬件成本高且容易损坏。提出了基于35k V配电线路的新型高压电能计量装置应用无线通信技术,包括微功率无线和GPRS无线,实现本地与远程通信的信息采集与传递,分析了其设计要点与功能。并且提出了无线脉冲方式校表,提高装置的安全性、可靠性,降低硬件设计成本。