【作者】 向泽；

【导师】 蒋兴良；

【作者基本信息】 重庆大学 ， 电气工程， 2014， 博士

【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。更多还原

【Abstract】 Transmission line icing is a serious problem that affects the safe operation ofpower systems. The accidents caused by icing, such as line disconnection, tower failure,and transmission lines galloping, seriously threaten the security and reliability ofelectric power networks.How to effectively predict the ice thickness and accurately monitor the icingprocess on the conductors has become an important research topic at home and abroad.It is very meaningful and vital for power grid to take timely anti-icing and de-icingmeasurement to avoid the occurrence of ice disaster. Many prediction models andmonitoring methods for transmission line icing have been proposed by many scholars.However, due to the complexity of the ice progress and inaccurate measurements of themodel parameters, the accuracy of the models has been questioned, and they are notwidely used in engineering. Therefore, to establish an accurate and efficient model forthe transmission line icing has important theoretical value for the power grid to designand construct anti-icing mitigation project. Additional, it can provide a reference for therelevant departments to take timely and reasonable anti-icing or de-icing measures.Supported by the National Basic Research Program of China (973program)(“transmission line icing failure forming mechanism and prediction model and controlmethods”) and the cooperation program (“early warning program and calculationmodel for transmission line icing”) with the EHV Maintenance Test Center of ChinaSouthern Power Grid, theoretical analysis and modeling, field observation andmeasurement and actual operation transmission lines tests are used to carry out theproject. The concrete research content is as follows:A long-term of observations and measurements are carried out in the XuefengMountain Natural Icing Stations (XMNIS) and the influence factors of the natural icingon the transmission lines are analyzed. Moreover, the typical section shape of glazeicing on conductors is studied and the correction coefficient of the actual non-uniformice is proposed as an accurate and convenient method for field icing measurement.Based on a lot of field measurement at XMNIS, the shape correction coefficient of thetypical glaze icing is analyzed and calculated.The wind load theory and the formula of the load calculation are analyzed. And theuse of harmonic synthesis simulation of fluctuating wind load in the time-domain method for modeling wind load is studied. The empirical formula and the aerodynamiccharacteristics calculation method of the trnansmission line wind load are studied andanalyzed. Moreover, a new method for wind load calculation is presented based on thechange of the transmission line load characteristics. Based on the data gathered atXMNIS, the wind load is calculated and compared with the results by empirical formulawhich verifies the correctness and feasibility of the proposed method.Based on the hydromechanical theory, the modeling method and the simulationmethod for the analysis of the aerodynamic properties of the crescent iced conductorand sector-shape iced conductor are put forward. The air flow map around the icedconductors is simulated. Besides, as to the iced conductors with different ice thicknessand wind speed, the lift coefficient and drag coefficient under different attack angles arecalculated. The influence law of ice thickness, wind speed and different cross sectionsof the iced conductor on the aerodynamic parameters of iced conductors can beobtained.The basic characteristics of the tension and tilt of the insulator string at the tangenttower after icing are analyzed. Based on the parameters of tilt and tension of theinsulator string at the tangent tower, a new mechanical calculation model is put forwardwhich considers the combined ice and wind loads.Based on a long-term observations and a great number of field experiments at theXMNIS, the proposed model is verified. Moreover, based on the implementing programby C++, the proposed model is applied to the actual transmission line. The on-linemonitoring data and field ice data obtained from the actual operation transmission linesof the China Southern Power Grid are used to verify the proposed ice thicknesscalculation model.更多还原