【作者】 李超；

【导师】 王辉； 黄维宪；

【作者基本信息】 三峡大学 ， 电气工程（专业学位）， 2018， 硕士

【摘要】 台风是一种破坏力很强的灾害性天气,给人类生命财产安全带来了极大的威胁。福建省地处东南沿海,濒临西北太平洋,受热带气旋的影响十分频繁。台风灾害会对福建地区配电网造成严重的破坏,进而对电力系统安全稳定运行产生巨大威胁。本文首先回顾了典型自然灾害风险评估方面的研究成果,并从台风灾害着手分析其风险评估方面的相关进展,进而回顾了台风天气下的电网风险评估研究成果;接着分析了典型台风“莫拉克”对福建省配电网的影响,并结合现场情况提出了解决措施和对策建议;然后介绍了台风风场风速计算理论,并对导线和电杆单元的材料、载荷、强度及可靠性进行了分析;最后从可靠度的角度对配电网线路进行了风险评估。主要结论如下:(1)断线、倒杆断杆是台风天气下配电网的主要破坏形式。在线路设计和改造过程中,需要特别注意微地形、微气象的差异,对重点区段加强防风措施,严格执行相关标准并认真研究沿海的台风气象,从而提高配电网线路的安全可靠程度。(2)导线的抗拉强度和混凝土电杆的抗弯强度均服从正态分布,其可靠性分别由悬挂点的截面应力和杆根处产生的弯矩所决定。随着风速的增大,导线悬挂点处的截面应力值增大。(3)在混凝土电杆直接承受风载荷时,在约束截面上,背风面应力均呈现应力大于迎风面的现象,且分布在杆身表面。在杆身迎风面中心线上,应力最大值均出现在支持点截面,随风速变化其值变化不大;在杆身背风面中心线上,最大值亦出现在支持点截面,随风速增大其值增加明显。(4)随着风速的增加,对于导线,线径最小的LGJ-70/10导线可靠度降低最快,而线径最大的LGJ-240/30则降低最慢。对于混凝土电杆,总体上来讲其下降比导线可靠度下降更快,且线径越大的导线下降越快。由于配电网线路中,同一条线路中的导线和电杆是串联关系,故线路可靠性是线路元件可靠性的乘积,当线路较长时可靠性较低。根据线路可靠性的计算结果,结合运行部门的要求,即可完成配电线路的风险评估。更多还原

【Abstract】 Typhoon is a type of disastrous weather phenomenon with great damage,and it could cause significant threats to human life and property security.Fujian province locates in the southeast coast and borders on the northwest Pacific Ocean,so it is frequently affected by tropical cyclone.Typhoon can cause severe damage to distribution network in Fujian region,and then threaten the safe and stable operation of electric power system.In this paper,firstly,risk assessmentresearches on typical natural disasters are reviewed,those ontyphoon are analyzed,and those on power grid in typhoon weather are reviewed.Secondly,effects of a representative typhoon “Morakot” on distribution network in Fujian province areanalyzed,and solutions and countermeasure suggestions are proposed according to the field situation.Then,the wind velocity theory of typhoon wind fieldis introduced,and materials,loads,strength and reliability are analyzed.Finally,risk assessment of distribution lines is performed based on the degree of reliability.The main conclusions in this paper are as follows.(1)Line breakage,pole collapse and pole breakage are the main failure modes of distribution network in typhoon weather.More attention should be paid to the differences in micro-landform and micro-climate in design and reconstruction of electric lines.Strengthening wind protection in priority areas,performing related standards strictly and studying typhoon information in coastal areas carefully should be done to improve security and reliability of distribution lines.(2)The tensile strength of wires and the bending strength of concrete poles are normally distributed,and the reliability of them is determined by the section stress of their suspension point and the bending moment of their root.For wires,the section stress of suspension point increases with the wind speed increasing.(3)When concrete poles are subjected to wind loads,the stress valuesof poles on the leeward side are greater than those on the windward side in the constraint section,and they are distributed on the surface of the poles.On the centerline of windward side of poles,the maximum stress appears in the constraint section,and it changes insignificantly with the wind speed.Although the maximum stress also appears in the constraint section for the leeward side,it increases significantly with the wind speed increasing.(4)The degree of reliability of wires decreases with the wind speed increasing,in which the wire with the smallest diameter,LGJ-70/10,has the fastest decreaserate,and the one with the largest diameter,LGJ-240/30,has the slowest decrease rate.Overall,the degree of reliability for concrete poles falls more rapidly than that for wires with the wind speed increasing,and it falls faster if the wire diameter is larger.In distribution network,the relation of wires and poles in the same line is in series,so the reliability of the line is the product of the reliability of the line components,which means that the reliability is low when the line is long.Based on the calculation results of line reliability,risk assessment of power distribution can be implemented by combining the requirements of the operation department.更多还原