干式电抗器绝缘故障的光纤光栅软测量机理与识别研究

In the dry-type air-core reactor, the normal state and the abnormal state of current, voltage and resistance doesn’t change significantly under the influence of inductance characteristics. Consequently, the online measurement of characteristic parameters is difficult. Based on the sensing and transmission of all-optical signal, the fiber provides a detection methods compatible with the electromagnetic environment of dry-type air-core reactor. The flexible interventional technique of fiber Bragg grating is introduced to embedded in the encapsulation structure of dry-type air-core reactor. The characteristic parameters is extracted to reflect the insulation fault of dry-type air-core reactor induced by the partial discharge, overheat, burn, and even fire burned. As a result, the technique route of soft sensor is introduced to provide the online measurement in the dry-type air-core reactor. And further the insulation fault correlation analysis model of random process is established on the consolidation strength variation during the process of high temperature curing and temperature rise, and the background data of temperature distribution and structural changes when powered on. The thermal-optical and dynamical-optical constitutive relations of multi-parameter coupled fiber Bragg grating are formulated, and determinate the insulation failure threshold responded the thermal field distribution, and the significantly affect or even destroy of device body in the transient procedure of reactor. Therefore, the apparent thermal strain and the applied stress-strain are absorbed from the failure mechanism and characteristic state. Eventually, for improving fault recognition rate and robustness, the insulation fault diagnosis model of dry-type air-core reactor is modeled by integrating the inverse analysis, state estimation, and time series analysis based on the measurement multi-parameter of the fiber Bragg grating.

在干式空心电抗器中，受自感特性的影响，电流、电压或阻抗在正常或异常状态下的变化不明显，且特征状态参量在线测量困难。基于全光信号的传感与传输，光纤提供了一种与干抗电磁环境相兼容的检测方式。研究光纤光栅埋入干抗包封结构的柔性介入技术。揭示干抗在实际运行中因局放、过热、烧伤甚至起火烧毁等引起的绝缘故障特征。从而为干抗的在线监测提供了一种软测量的技术路线。并进一步根据高温固化和升温过程中的包封固化强度变化规律，以及通电状态时的温度分布和结构变化等背景数据，建立随机过程的绝缘故障相关分析模型。建立干抗多参量耦合的光纤光栅热-光、力-光等本构关系，确定反映热场分布以及瞬变过程对器身产生的严重影响甚至破坏的绝缘故障阈值，从故障机理和特征状态还原表观热应变与外加应力应变。最终建立一种基于光纤光栅多元测量参数的综合反演分析、状态估计和时序分析的干抗绝缘故障识别模型，提高故障的识别率和鲁棒性。

在干式空心电抗器中，受自感特性的影响，电流、电压或阻抗在正常或异常状态下的变化不明显，且特征状态参量在线测量困难。基于全光信号的传感与传输，光纤提供了一种与干抗电磁环境相兼容的检测方式。本课题研究了光纤光栅埋入干抗包封结构的柔性介入技术，形成集信号传输与智能感知于一体的多参量检测与状态评价。研究干抗在实际运行中因局放、过热、烧伤甚至起火烧毁等引起的绝缘故障所表现出来的状态特征，将难以在线监测的干抗绝缘参量转换为可被光纤光栅传感器在线监测的过程变量，从而为干抗的在线监测提供了一种软测量的技术路线。研究了将光纤光栅传感器检测干式空心电抗器关键参量的安装技术与关键控制参量，并进一步在干抗的高温固化中成型，同时提供基于光纤光栅传感器的器身固化过程中的温度和应力应变的参数响应变化过程。建立了基于铝-绝缘结构的干式电抗器三维物理模型，对干式电抗器的在温度场和电动力导致的外加应力应变进行数值建模和分析，其关键问题是确定干式电抗器的有限元网格模型、热源和边界条件。通过对历史电抗器损坏数据进行统计分析，并对干式空心电抗器的损坏进行反演分析。对故障类型分类，匝间短路和局部过热为事故发生的主要表现，温度对包封的绝缘材料的作用是引起包封安全运行的重要原因，通过模糊数学的方法更准确地确定了包封对于温度因素的可靠度。结合典型绝缘材料的老化经验公式和实验，引入蒙特申格尔寿命定律建立干式电抗器关键控制性材料的使用寿命与模型。建立干抗多参量耦合的光纤光栅热-光、力-光等本构关系，确定反映热场分布以及瞬变过程对器身产生的严重影响甚至破坏的绝缘故障阈值，从故障机理和特征状态还原表观热应变与外加应力应变。根据干式电抗器仿真计算结果，进行干式空心电抗器温升实验，在线监测电抗器的温升及应力应变数据。最终建立一种基于光纤光栅多元测量参数的综合反演分析、状态估计和时序分析的干抗绝缘故障识别模型，提高故障的识别率和鲁棒性。