【作者】 贾丹平；

【导师】 苑玮琦；

【作者基本信息】 沈阳工业大学 ， 电机与电器， 2008， 博士

【摘要】 随着电力系统容量的日益扩大和电网电压运行等级的不断提高,传统的电磁式互感器表现出越来越多的弱点,难以满足电网向自动化和数字化发展的需求,电子式高压电流互感器取代传统的电磁式互感器已成为发展的必然趋势。但迄今为止其研究领域依然充满难题,阻碍着电子式电流互感器的实用化进程。本文提出一种测温式光纤电流互感器方案,把电流的热效应和光纤测温技术结合起来,实现对电流的测量。光纤温度传感器是发展最早、技术最成熟的光纤传感器产品,而电流热效应技术的应用更普遍,因此新方案较之当前主要方案,存在明显技术优势。新方案还可用于直流测量,适应当前直流输电发展需要。论文中推导了被测电流瞬时值与温升的关系,得到光纤电流互感器的数学模型,利用这一模型,理论上证明了传感器温度输出能准确跟随电流瞬时幅值的变化,量值上有确定关系,能够用来测量电流瞬时值的绝对值。通过数学模型,得到了主要部件应满足的技术指标及性能要求,为部件的设计提供基础。仿真与实验证实了理论分析的正确性。分析了主要功能部件的技术现状。其中电流温度转换装置仿真计算其热力学特性,通过结构参数论证技术可行性;电流采样部件用罗氏线圈和标准电阻分流器,分析了设计要求和商品器件技术参数。测温装置采用已经商品化的荧光余辉测温方案,由于当前荧光测温性能与理论性能还有一定差距,通过理论与实验分析,提出了进一步提高性能的方法,包括:(1)分析导致荧光测温性能与理论性能有一定差距的主要原因,是实际的荧光余辉的非指数变化倾向。这一发现可用来开发高性能的荧光余辉测温装置;(2)提出截断归一化方法,通过图解和计算,得到荧光余辉非指数倾向程度的量化指标,用来优选荧光材料;(3)提出优化荧光余辉测温装置的设计概念,即物理现实、数学模型及数据处理方法要尽可能匹配,才能有效的提高装置测温性能;(4)仿真与实验验证了上述理论与方法的有效性。分析了新方案在交流电流和直流谐波等方面应用的可能性,研制成荧光余辉测温装置,组成电流互感器实验装置。实验结果证实理论分析的有效性。更多还原

【Abstract】 As the capability and voltage level of transmission lines increasing,conventional inductive current transformers have several draws at extra-high voltage,and particularly ultra-high voltage grades.High voltage elecronic current transformers(ECT) replacing conventional transformers will be the certain developing tendency.However the unsolved problems are in the way to ECT’s practicality up to the present time.A high voltage current transformer project based on current thermal effect was introduced,which combined the current thermal effects and the optical fiber thermometry technology.Fiber optic temperature sensor was the earlier and the mature product among fiber optic sensors in commercial,current thermal effects technology is more general applied,so the new project has the advantages over other current transformer projects which are now meeting the difficulties hardly to resolve.It can be used to measure direct current is another significance advantage.The relationship between the instantaneous value of measured current and the temperature rise was deduced,and the mathematical model of the current transformer was established.By use of the mathematical model,in theory,the amplitude of instantaneous current can be tracked by the temperature output of sensor accurately,so that it can be used to measure the absolute value of instantaneous current.The technical data and features required of the main devices and components can be provided by use of the mathematical model for technical design of the project,simulation method and experiment tests were used to prove the available.The realization of the main devices and components were analyzed.The thermodynamic properties of the current temperature conversion device were calculated by the ANSYS software,the mature Rogowsky’s coil or ohmic shunt was used as the current sample device.The design requriements and commercial components’s technical parameters were analyzed. Fluorescent decay temperature measurement principle was used to measure the temperature,for improving the performance of this kind of method as it has not yet reach the theoretical predict,an optimization method of enhancing the performance was brought forward,which including:(1) The trend of non-exponential variation of the actual fluorescent decay curve is the main factor leading to the result that the temperature measurement performance is not as good as describe by theoretical predict.This result can be used to promote the performance of the temperature measurement system.(2) A cutting and normalized method is given by graphic and caculating to get the numerical factor about the non-exponential degree of the fluorescent decay curve.It can be use to select the predominance fluorescent materials.(3) The concept of the matching of physical reality with mathematical models and data-processing methods can effectively raises the temperature measuring performance.(4) Experiments and simulations proved the effectiveness of the above theory and method.Applied possibility in AC、DC and harmonic wave by using this project were analyzed.The fluorescent decay temperature measurement device was developed,and was assembled into current transformer experimental equipment.The validity of theoretical analysis was proved by the experimental results.更多还原