【作者】 张云鹏；

【导师】 刘宪林；

【作者基本信息】 郑州大学 ， 电力系统及其自动化， 2012， 硕士

【摘要】 为了适应现代大规模电力系统的需要,建设坚强精准的通信系统,现代电力系统中采用光纤复合架空地线(OPGW)作为一侧架空地线的现象越来越普遍。然而,在电力系统发生故障或遭受雷击过电压(持续时间短)时,OPGW中会流过比较大的电流,此电流的热效应将使导线温升过高,严重时会毁坏其内部复合的光纤,导致电力通信瘫痪。实际电力系统的输电线路结构复杂,如何提高OPGW最大故障电流的计算精度,为其热稳定校验提供依据是个亟待解决的问题。论文着重对电力系统复杂结构输电线路接地故障及此时OPGW的电流分布问题进行建模计算和相关分析,其主要工作和研究成果如下。论文基于相分量法进行OPGW分布电流计算模型及算法研究。模型研究。复杂结构输电线路的主要模型包括线路模型和终端模型两部分,其模型的建立过程如下：(1)线路模型采用的是计及相线系统和地线系统的相互影响的扩展相分量法,它是对相分量法的扩展。扩展相分量法把相线系统和地线系统合并建模,模型中的每基杆塔处,各导线都通过一个虚拟电阻与杆塔相连,若导线与杆塔直接相连虚拟电阻为零,导线与杆塔绝缘虚拟电阻为无穷大。如此,调节虚拟电阻取值可描述杆塔的各种接线方式。(2)线路终端分为电源终端与负荷终端。电源终端采用基于相分量法的多端口戴维宁等值模型。负荷终端处假设其与外部系统没有连接,为保证模型的统一性,在变电站出口至变压器中性点段补全相线系统,取该档相线的自阻抗为无穷大。(3)对于复杂结构输电线路,根据线路结构相同原则,把复杂线路分割成块,全线由多个子区间构成,每个子区间根据杆塔的数量不同分为相应的档位。对每个子区间使用基于相分量法原理扩展后的扩展相分量法进行建模计算,然后再把各块通过交接点联系起来合并计算,得到复杂网络的OPGW故障电流计算的全模型。算法确定。根据扩展相分量法建立的全线模型,数据量比网孔法大很多倍。为了克服这种缺点,根据系数矩阵的块三对角特性,论文采用“追赶法”化简求解,大大提高了计算速度,弥补了计算量大的不足。应用与实例。(1)利用论文模型对简单线路实例进行分析可知：扩展相分量法的计算结果与传统的网孔法的计算结果的曲线走势吻合良好,说明了扩展相分量法的合理性；从其计算结果的对比可发现,扩展相分量法较传统算法的OPGW故障电流值大10%左右。(2)论文采用扩展相分量法和交接点的原理,对某非洲城网进行相关分析与计算：对于某杆塔处故障,OPGW故障电流分析程序给予详细的OPGW故障电流分布情况；程序实现故障点自动循环功能,能得到OPGW最大故障电流的分布曲线,根据曲线,容易得到最严重情况下的故障电流分布。这为该城网的OPGW选型提供了参考依据。扩展相分量法实现了地线系统和相线系统的统一运算,避免了由于部门分工,忽略地线系统和相线系统相互影响等因素造成的OPGW最大故障电流的计算误差；扩展相分量法与交接点原理相结合,解决了复杂结构输电线路的OPGW故障电流分布计算研究；论文方法还可以得到在架空地线影响下的相线系统故障电流的分布情况；扩展相分量法较传统算法的OPGW故障电流值大,说明传统算法的计算结果偏于乐观；对于OPGW的最大故障电流计算,复杂结构输电线路接地故障程序能够自动实现各杆塔以次作为故障点的运算,最终由各杆塔故障的情况下的OPGW最大故障电流形成OPGW的最大故障电流曲线。总之,扩展相分量法更能直观、准确地找到OPGW的最严重情况下的故障电流,为OPGW的选型提供可靠的依据,为电力系统的可靠运行和经济建设提供有力的保证。因此,这无论是对OPGW选型校验,还是对电力系统故障分析,都有重要意义。更多还原

【Abstract】 In order to adapt to the needs of the modern large-scale power system and build a strong and accurate communication system, Optical Fiber Composite Overhead Ground Wire (OPGW) as a phenomenon of the side of the overhead ground wire is commonly used in modern power system. However, when fault occurs in power system or power system is struck by lightning over-voltage(short duration), the relatively large current will flow through OPGW, the heating effect of current will increase the temperature of wires, even devastate its internal composite fiber, and result in paralysis of the electric power communications. The structure of actual power system transmission lines are complex, how to improve the calculation accuracy of the OPGW’s maximum fault current to provide the basis for its thermal stability verification is an urgent problem. The thesis focuses on the line ground fault of the power system’s complex transmission structure and the OPGW current distribution in the modeling calculations and correlation analysis, the main work and results are as follows.The research of this OPGW thesis is on the distribution of the current computational model and algorithm, which is based on the phase component method.The research of model. The complex structure of the transmission line model consists of two parts, the line model and the terminal model, the building process of the model is as follows:(1)Line model adopts an extension component method which takes the mutual influence into account between the phase line system and ground system, and it is the extension of the phase component. Extension component method takes phase line systems and ground systems into modeling, in the model each wire is connected with the tower through a virtual resistor. If wire is directly connected to tower, the virtual zero resistance, and if the wire and the tower is insulation, the virtual resistance is infinite. So, adjusting the virtual resistor values can describe the variety wiring of towers.(2)The line terminal is divided into the power supply terminals and load terminals. The power supply terminal uses multi-port Thevenin equivalent model which is based on phase component. The load terminal at the assumption is not connected with the external system, in order to ensure the unity of the model, exports in the substation to transformer neutral point of fill phase line system take the file line impedance is infinite.(3) According to the same principles of the line structure, the complex structure of transmission lines are split into blocks, and across the board by multiple sub-intervals, so each subinterval according to the number of towers are divided into the appropriate gear. On each subinterval using the model based on the expansion of the phase component in the principle of expansion phase component method, and then blocks are linked together by the intersection, and the OPGW fault current calculated by the full model of the complex network.Algorithm to be determined. According to the extended phase components method we establish the whole line model, whose amount of data is many times greater than the method of mesh method. In order to overcome this disadvantage, according to the block tri-diagonal characteristics of the coefficient matrix, this paper uses "chasing method" to simplify and solve, which greatly improves the computational speed, and makes up the deficiency of large computational complexity.Applications and examples.(1) Using the proposed model to analysis the simple circuit we can learn the result curves using extended phase components method are in good agreement with the curves using the traditional mesh method, which shows the rationality of the extended phase component method; From the comparison of the calculation results we can find that, by using the extended phase component method compared to using the traditional algorithm the OPGW fault current values are bigger about10%.(2) This paper uses the extension phase component method and the principle of the junction points to analysis and calculate the Africa city network; the programs of the OPGW fault current analysis give the details of the OPGW fault current distribution; Also the programs can realize the fault points automatic circulation function, and can get OPGW maximum fault current distribution curve, according to the curve, it is easy to get the fault current distribution under the most severe case This provides the reference to the city net OPGW selection.The extended phase component method can achieve the unifying admittance calculation of earth wire system and phase wire system, and avoid OPGW maximum fault current calculation error caused by factors such as ignoring mutual influence of earth wire system and phase wire system when work are divided; combined with extended phase component method and the principle of junction point, we can solve the calculation problems of OPGW fault current distribution in complex structure of transmission line; Using the method proposed in this paper can also obtain the fault current distribution in the phase wire system under the influence of the overhead ground wire line; The OPGW value of fault current calculated by using expanded phase component method are bigger than the traditional algorithm, which illustrates that the calculating results of traditional algorithm are overly optimistic; for the OPGW maximum fault current calculation, grounding fault programs of the complex transmission line can automatically run the calculation for each tower in turn served as the fault point, in the end, according to the OPGW maximum fault current in the case that tower is served as the fault point, we can draw the OPGW maximum fault current curve.In short, the extended phase component method can visually and accurately find OPGW fault current in the most serious cases, which provides a reliable basis to the selection of the OPGW modeling, and provides a strong guarantee to the reliable operation of the power system and economic development. Therefore, it has an important significance for both OPGW type checking and fault analysis of power system.更多还原