具有温度自补偿功能的宽频带光纤电场传感器

Broadband Optical Fiber Electric Field Sensor with Temperature Self-compensation

光纤电场传感器抗电磁干扰能力强、响应速度快,在电力设备运行状态和绝缘状况的监测领域有着广阔的应用前景。现有的光纤电场传感器由多个不同功能的分立光学器件组合而成,光路耦合对准困难、光功率损耗大、灵敏度低。此外,温度交叉敏感问题进一步限制了传感器的实际工程应用。为克服现有技术难题,提出一种以特种功能光纤取代分立光学器件,进而形成全光纤电场传感器的技术思路。传感器中的起偏器、检偏器、波片等功能器件均在光纤上实现,避免了分立元件之间对准、耦合等带来的传感器结构不稳定、性能低等问题。此外,通过双晶体正交级联光路结构的设计,赋予传感器温度自补偿功能,实现对温度交叉敏感的有效抑制。实验结果表明,传感器可同时对50 Hz低频电场和纳秒级脉冲电场进行有效捕获,环境温度变化给测量结果带来的误差仅为0.1%/℃。全光纤电场传感器结构简单、稳定性好、测量频带宽,在电力设备快速暂态过电压的测量方面有着重要的潜在应用价值。

Optical fiber electric field sensors have many advantages such as immune to electromagnetic interference and fast response dynamics,thus this type of devices has great potentials in the field of condition monitoring and insulation status diagnosis of power equipment.The existing sensors are generally composed of many discrete components,which results in low coupling efficient,high loss,and low sensitivity.Moreover,temperature cross-sensitivity is a big issue when comes to practical applications.To counterbalance the above drawbacks,we proposed a new type of optical fiber electric field sensor in which a special functionalized fiber is utilized to replace conventional discrete components.The polarizer as well as waveplate are integrated as fiber-in-line structure,consequently the shortcomings of unstable structure and low performance caused by alignment accuracy and coupling efficient between discrete components can be avoided.Additionally,temperature cross-sensitivity can be suppressed via cascading two crystals orthogonally.The experimental results show that the measurable frequency range covers 50 Hz to 200 MHz and the temperature cross-sensitivity is as low as 0.1%/℃.Thanks to the features of compact size,high stability,and broadband measurement range,the proposed sensor can be used for very fast transient overvoltage(VFTO)measurement of power equipment.