基于混合量测的电网运行状态评估技术研究

发布时间：2018-11-06 09:37

【摘要】：智能电网的建设给电力行业的发展带来了机遇和挑战,随着电动汽车和大型电力电子设备接入电网,电网的结构将变得越来越复杂,电网的运行状态必将会受到严重的影响。电网运行状态的好坏直接关系到电力系统生产和运行的安全稳定。因此,对于电网运行状态评估技术的研究显得尤为的重要。从电网运行状态评估中的潮流计算出发,本文通过研究输电线路的热平衡方程,明确了输电线路导体的能量转化机制,分析了电力元件之间的热阻模型,并对热平衡方程进行了适当的化简。通过改进牛顿-拉夫逊潮流算法,将环境温度因素引入到了电力系统潮流计算中。以牛顿-拉夫逊潮流算法为载体,在该算法中增加了支路导体温度作为系统的状态变量,从而扩展了雅克比矩阵,通过建立无功、有功不平衡量与温度、电压、相角之间相互依赖的耦合模型,实现对扩展的雅可比矩阵的不断迭代。之后在该模型的基础上对电网潮流进行了分析,以MATLAB为工具进行编程实现了算法的功能,并与牛顿—拉夫逊潮流算法结果进行对比,通过仿真分析IEEE 39节点系统,验证了该方法的有效性。仿真分析了考虑环境温度的潮流算法和牛顿-拉夫逊潮流算法在线路损耗、线路电阻和节点电压上的变化值,分析结果显示在考虑环境温度影响后,电网的潮流信息将发生显著的变化,并且随着温度的不断上升,这种变化程度将愈加的明显。通过对电网中的多指标数据进行分析,本文提出了一种基于灰色密切值的综合评估模型。主观权重值的获取采取传统的专家赋权的层次分析法,考虑到电力系统在长期运行过程中,指标数据值不能单独的存在,各指标数据值之间必将存在着相互联系、相互作用,因此通过熵权法、变异系数法、CRITIC法三种客观赋权方法得到客观权重并进行分析,采取博弈论离差最小的方式来得到客观权重,将改进的Kendall和谐系数引入到主客观权重的赋权中,最终得到权重值。将研究小数据、贫信息和不确定问题的灰色关联度方法与传统的密切值方法相结合,提出了基于几何趋势和几何距离的灰色密切值方法用于电网多指标数据的分析中。针对某地区电网的实际情况进行分析综合,从安全运行、经济效益、环保清洁三个方面建立了电网运行评估指标模型,并对各个指标给予了明确定义。采集和计算现有的电网数据,运用灰色密切值评估模型对某电网五日运行情况进行了比较,得到了指标评估结果,用于指导分析具体日的运行情况。
[Abstract]:The construction of smart grid brings opportunities and challenges to the development of power industry. With electric vehicles and large power electronic equipment connected to the grid, the structure of power grid will become more and more complex, and the operation state of power grid will be seriously affected. The operation state of power system is directly related to the safety and stability of power system production and operation. Therefore, it is very important to study the evaluation technology of power grid operation state. Based on the calculation of power flow in power network operation state evaluation, the heat balance equation of transmission line is studied in this paper, the energy conversion mechanism of transmission line conductor is clarified, and the thermal resistance model between power elements is analyzed. The heat balance equation is simplified appropriately. By improving Newton-Raphson power flow algorithm, the ambient temperature factor is introduced into power system power flow calculation. The Newton-Raphson power flow algorithm is used as the carrier, and the branch conductor temperature is added as the state variable of the system. The Jacobian matrix is expanded by establishing reactive power, active power imbalance, temperature and voltage. The mutually dependent coupling model of phase angles realizes the continuous iteration of the extended Jacobian matrix. On the basis of this model, the power flow of the power network is analyzed, and the function of the algorithm is realized by programming with MATLAB, and compared with the result of Newton-Raphson power flow algorithm, the IEEE 39-bus system is analyzed by simulation. The effectiveness of the method is verified. The power flow algorithm considering ambient temperature and Newton-Raphson power flow algorithm are simulated and analyzed in terms of line loss, line resistance and node voltage. The results show that the influence of ambient temperature is considered. The power flow information of the power grid will change significantly, and with the rising of temperature, the change will become more obvious. This paper presents a comprehensive evaluation model based on grey close value through the analysis of multi-index data in power network. The traditional analytic hierarchy process (AHP) of expert weight is used to obtain the subjective weight value. Considering that the index data value can not exist independently in the long-term operation of power system, there must be mutual relation and interaction among the index data values. Therefore, the objective weight is obtained by entropy weight method, variation coefficient method and CRITIC method, and the objective weight is obtained by using the minimum deviation of game theory. The improved Kendall harmony coefficient is introduced into the weight of subjective and objective weights, and the weight value is obtained. In this paper, the grey correlation degree method for the study of small data, poor information and uncertainty is combined with the traditional close value method, and a grey close value method based on geometric trend and geometric distance is proposed for the analysis of power grid multi-index data. This paper analyzes and synthesizes the actual situation of a certain area's power network, establishes the evaluation index model of power network operation from three aspects of safe operation, economic benefit and environmental protection and cleanness, and gives a clear definition of each index. The current grid data are collected and calculated, and the grey close value evaluation model is used to compare the operation of a power network for five days, and the evaluation results are obtained, which can be used to guide the analysis of the operation situation of a specific day.
【学位授予单位】：济南大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TM711

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