基于极化谱解谱法的变压器油纸绝缘等效电路建模及老化诊断

发布时间：2018-01-17 02:24

本文关键词：基于极化谱解谱法的变压器油纸绝缘等效电路建模及老化诊断　出处：《福州大学》2014年硕士论文　论文类型：学位论文

【摘要】：本课题基于国家自然科学基金资助项目《基于电路分析法和恢复电压响应的油纸绝缘老化诊断方法》(编号：61174117)。油纸绝缘变压器作为电力系统中的枢纽设备,其运行的可靠性影响着整个电网运行的安全性。回复电压法是一种无损电气诊断方法,它能够提供大量的绝缘老化信息。在运用回复电压法诊断变压器绝缘状态时,变压器的绝缘结构、湿度、温度等都会对结果产生影响。为了深入研究极化谱与回复电压特征参数和变压器绝缘状态之间的关系,在实验室建立模拟实验平台并对扩展德拜模型的等效电路进行了设计,通过实验仿真诊断了变压器油纸绝缘的老化状态。本文研究的主要工作是：1.以德拜介质响应模型为基础,提出了一种辨识单一极化支路和两条极化支路的等效电路参数的数学解析法,并验证了其正确性,为变压器油纸绝缘等效电路参数辨识提供了一个新的方法。严格推倒出回复电压峰值的计算公式,验证了利用极化谱判断油纸绝缘老化特性的可行性。仿真结果反映了对极化谱的研究可以很好的分析油纸绝缘的弛豫过程,为分析影响变压器绝缘老化因素提供了新的思路。2.通过改变等效电路参数来模拟变压器绝缘状态的改变。分析了在极化支路时间常数改变的情况下等效电路参数改变对变压器绝缘系统的老化状态的影响,即大时间常数的变化主要反映固体绝缘的老化状态,小时间常数支路反映变压器绝缘油的老化状态；对同一变压器,在主时间常数相同的情况下,回复电压峰值越小、初始斜率越小,反映变压器绝缘性能越好。引入吸收比和极化指数两个预试电气绝缘参数进行研究,得到判断变压器绝缘状况的另一种方法。3.在实验室建立回复电压模拟实验平台,通过对极化/去极化电流曲线的分析,提出了一种通过拟合去极化电流曲线来辨识等效参数的方法和用于拟合去极化电流曲线的表达式。基于实验室建立的回复电压模拟实验平台得到的数据,通过对参数进行计算和Matlab/simulink的仿真分析,验证了通过拟合去极化电流曲线来辨识等效模型参数的正确性。通过改变扩展德拜模型等效电路参数研究了等效电路参数与极化／去极化电流之间的关系,验证了通过极化／去极化电流曲线诊断变压器绝缘老化的可行性,也为通过极化／去极化电流曲线研究变压器油纸绝缘老化提供了新的方法。
[Abstract]:This subject is based on the project supported by the National Natural Science Foundation of China < diagnosis method of Oil-Paper Insulation Aging based on Circuit Analysis and recovery Voltage response "(No.: 61174117). Oil-paper insulated transformer is a pivotal equipment in power system. The reliability of its operation affects the safety of the whole power system. The reverse-voltage method is a non-destructive electrical diagnosis method. It can provide a large amount of insulation aging information. In the application of the method of voltage recovery diagnosis of transformer insulation, transformer insulation structure, humidity. In order to study the relationship between polarization spectrum and characteristic parameters of recovery voltage and insulation state of transformer. The simulation experiment platform is established in the laboratory and the equivalent circuit of the extended Debye model is designed. The aging state of oil-paper insulation of transformer is diagnosed by experimental simulation. The main work of this paper is: 1. Based on Debye medium response model. A mathematical analytical method for identifying the equivalent circuit parameters of a single polarization branch and two polarization branches is proposed, and the correctness of the method is verified. This paper provides a new method for parameter identification of transformer oil-paper insulation equivalent circuit. The feasibility of using polarization spectrum to judge the ageing characteristics of oil-paper insulation is verified. The simulation results show that the study of polarization spectrum can well analyze the relaxation process of oil-paper insulation. This paper provides a new way of thinking for analyzing the factors affecting the insulation aging of transformers. 2. By changing the equivalent circuit parameters to simulate the change of the insulation state of the transformer, the equivalent circuit is analyzed under the condition of the change of the time constant of the polarization branch circuit. The influence of parameter change on the aging state of transformer insulation system. The change of large time constant mainly reflects the aging state of solid insulation, and the small time constant branch reflects the aging state of transformer insulation oil. For the same transformer, when the main time constant is the same, the smaller the peak value of the recovery voltage, the smaller the initial slope. The better the insulation performance of transformer is, the study is carried out by introducing two pre-test electrical insulation parameters, absorption ratio and polarization index. Another method to judge the insulation condition of transformer is obtained. 3. The simulation experiment platform of the reverse-voltage is established in the laboratory, and the polarization / depolarization current curve is analyzed. A method to identify the equivalent parameters by fitting the depolarization current curve and an expression to fit the depolarization current curve are presented. Through the calculation of the parameters and the simulation analysis of Matlab/simulink. The validity of the equivalent model parameters is verified by fitting the depolarization current curve, and the relationship between the equivalent circuit parameters and the polarization / depolarization current is studied by changing the equivalent circuit parameters of the extended Debye model. The feasibility of diagnosing transformer insulation aging by polarization / depolarization current curve is verified. It also provides a new method for studying transformer oil paper insulation aging through polarization / depolarization current curve.
【学位授予单位】：福州大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM855

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