基于输电线路动态荷载的导线等值冰厚计算模型研究

发布时间：2018-05-06 16:49

本文选题：输电线路 + 计算模型　；参考：《重庆大学》2014年博士论文

【摘要】：架空线路覆冰是影响电网安全运行的重要问题之一，导线覆冰将引发舞动、断线、倒塔及绝缘子闪络等重大事故，严重威胁着电网的安全可靠运行。如何有效预测输电线路覆冰厚度及准确监测导线覆冰增长，成为国内外重要研究课题，对于电网覆冰后及时采取防冰、除冰措施，从而避免重大冰害事故的发生有重要意义。国内外学者提出了众多导线覆冰预测模型，然而由于覆冰影响因素复杂、模型参数测量不准确等原因，使得模型计算的精确性受到质疑，在工程中没有得到广泛应用。因此，建立准确的导线覆冰厚度预测模型、对导线覆冰增长过程进行准确地监测，不仅对电网防冰减灾设计和建设有着重要的理论参考价值和学术意义，还能为相关部门及时采取合理的防冰、除冰措施提供参考依据。本文依托国家重点基础研究计划973项目和南方电网超高压检修试验中心《输电线路覆冰预警方案与计算模型研究》项目，通过理论分析、仿真模拟、现场观测及实际运行线路验证等方法，，开展了以下研究工作：在雪峰山自然覆冰试验站对导线自然覆冰进行长期现场观测，分析了导线自然覆冰增长及影响因素；基于传统量器具测量法和人工描绘导线覆冰截面形状换算法，提出了用于现场人工测量导线覆冰厚度的覆冰形状校正方法，并通过大量现场试验观测，得到了雪峰山试验站导线覆冰形状校正系数。分析了风荷载产生原理及其计算方法，研究了谐波合成法模拟脉动风的数值模拟方法；并研究了输电线路风荷载经验计算公式及气动力特性计算方法，基于导线荷载特性变化提出了等效计算风荷载的新方法，利用雪峰山试验站采集的数据计算了导线风荷载，通过与经验公式法计算结果的对比，验证了该方法的合理性。基于流体力学理论，建立了新月形和扇形截面覆冰导线空气动力参数仿真模型并提出了数值模拟方法，通过数值仿真分析了覆冰导线周围空气流场，研究了两种截面覆冰导线在不同迎风攻角、风速、覆冰厚度条件下的升力系数和阻力系数，得到了风速、覆冰厚度和覆冰截面形状对覆冰导线空气动力参数的影响规律。针对现有导线覆冰计算模型未考虑风荷载引起的导线荷载特性变化或考虑不当问题，运用力学原理并结合导线覆冰增长特性，以绝缘子串悬挂点拉力、倾角为基本参量，综合考虑冰风荷载影响因素，系统地建立了绝缘子串不同布置方式下（耐张串、I串及V串）输电线路综合荷载等值冰厚计算模型。根据雪峰山自然覆冰试验站长期大量的现场观测和数据采集，对建立的综合荷载等值冰厚计算模型进行了试验验证；同时应用C++开发相应实现程序，将等值冰厚计算模型挂网于南方电网实际运行线路进行工程应用，利用覆冰监测终端的监测数据和采集的现场覆冰数据对建立的模型进行了验证。
[Abstract]:The icing of overhead lines is one of the important problems that affect the safe operation of the power network. The icing of conductors will lead to major accidents, such as galloping, wire breakage, inverted tower and insulator flashover, which seriously threaten the safe and reliable operation of the power grid. How to effectively predict the icing thickness of transmission lines and accurately monitor the ice growth of conductors has become an important research topic at home and abroad. It is of great significance to take anti-icing and de-icing measures in time after icing in power grid, thus avoiding the occurrence of major ice damage accidents. Scholars at home and abroad have put forward many models for prediction of conductor icing. However, due to the complexity of icing factors and inaccurate measurement of model parameters, the accuracy of model calculation has been questioned and has not been widely used in engineering. Therefore, it is not only of great theoretical reference value and academic significance to establish an accurate prediction model of conductor icing thickness and to monitor accurately the process of conductor icing growth, but also for the design and construction of anti-icing disaster reduction in power network. It can also provide reference for relevant departments to take reasonable anti-ice and deicing measures in time. This paper relies on the national key basic research plan 973 project and the project "study on early warning Scheme and Computational Model of Transmission Line icing" in the EHV maintenance Test Center of Southern Power Grid, through theoretical analysis, simulation and simulation. The following research work has been carried out: In Xuefeng Mountain natural icing test station, the natural icing of conductors was observed for a long time, and the growth of natural ice and its influencing factors were analyzed. A correction method of icing shape is proposed for measuring the ice thickness of conductors in the field, and the correction coefficient of the icing shape of conductors in Xuefeng Mountain Test Station is obtained by a large number of field test observations. The principle of wind load generation and its calculation method are analyzed, the numerical simulation method of harmonic synthesis method for simulating pulsating wind is studied, and the empirical formula for wind load calculation and aerodynamic characteristics calculation method of transmission line are studied. Based on the variation of traverse load characteristics, a new method for equivalent wind load calculation is proposed. The wind load of conductor is calculated by using the data collected from Xuefeng Mountain Test Station. The rationality of this method is verified by comparing with the results of empirical formula method. Based on the hydrodynamics theory, the aerodynamic parameters simulation models of crescent and sector-shaped ice-coated conductors are established and the numerical simulation method is proposed. The air flow field around ice-coated conductors is analyzed by numerical simulation. The lift coefficient and drag coefficient of two kinds of ice-coated conductors under different upwind attack angle, wind speed and ice thickness are studied. The influence of wind speed, ice thickness and ice section shape on aerodynamic parameters of ice-coated conductors is obtained. In view of the fact that the current calculation model of conductor icing does not consider the change of traverse load characteristics caused by wind load or the problem of improper consideration, the basic parameter is the suspension point tension and inclination angle of insulator string, which is based on the mechanics principle and the characteristics of conductor icing growth. Considering the influence factors of ice wind load, the equivalent ice thickness calculation model of transmission line under different arrangement of insulator string (tension string I string and V string) is established systematically. Based on a large number of field observation and data collection in Xuefeng Mountain Natural icing Test Station, the calculation model of equivalent ice thickness under comprehensive load is tested and verified, and the corresponding program is developed with C, The equivalent ice thickness calculation model is applied to the practical running line of Southern Power Grid, and the model is verified by the monitoring data of the icing monitoring terminal and the field icing data.
【学位授予单位】：重庆大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TM752

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