电力系统频率动态分析与自动切负荷控制研究

发布时间：2018-06-28 11:00

本文选题：电力系统 + 频率稳定　；参考：《西南交通大学》2014年博士论文

【摘要】：电力系统频率反应了系统中有功功率的供需平衡情况,是电力系统运行的重要指标。当超特高压输电线路因故障退出运行、系统解列或者大容量机组退出运行时,可能造成系统较大的有功缺额,严重时将会导致系统频率失稳。扰动后电力系统频率动态特性分析是电力系统频率稳定分析和控制的基础。目前常用的电力系统频率稳定分析方法有单机等值模型法和时域仿真法。单机等值模型法无法考虑系统网络、负荷对系统频率动态的影响；时域仿真法计算量大,难以实现在线应用。广域量测系统实时监测电网状态,为电力系统的分析与控制提供了新的手段。利用系统的广域量测数据,论文主要从电力系统频率分析方法、频率安全稳定在线评估、频率稳定自动切负荷控制等方面开展研究,主要研究工作如下：(1)燃煤电厂锅炉及辅机设备对电力系统频率动态影响。传统的频率动态研究方法忽略了锅炉、辅机对系统频率动态的影响。在系统频率响应模型的基础上,建立了一个包含电厂锅炉、辅机及机组控制系统的简单闭环模型,用于电力系统频率动态研究。该闭环模型计及了锅炉效应及由厂用电驱动的辅机设备的频率效应。仿真对比研究了不同扰动功率情况下,系统锅炉、辅机设备对系统频率动态的影响。探讨了在频率动态分析时如何考虑锅炉、辅机设备的影响。(2)频率动态分析方法。提出了一种基于扰动前后系统广域量测数据的电力系统频率动态分析方法。该方法首先对扰动后系统的网络进行化简,消去系统的联络节点；然后对系统的网络方程、负荷方程、发电机运动方程和原动机-调速器动态方程进行线性化,建立扰动后系统的状态方程和输出方程。利用扰动前后系统的广域量测数据,对系统的状态方程进行求解,计算扰动后系统惯性中心频率。通过与PSS/E仿真结果进行比较,该方法能够准确描述扰动后系统频率的动态特性。(3)频率安全稳定在线评估方法。提出了一种基于扰动前后系统广域量测数据和Amoldi模型降阶方法的扰动后系统频率最低值的快速预测算法。对扰动后系统状态方程及输出方程进行初等变换；利用Amoldi模型降阶方法,对初等变换后的系统状态方程与输出方程进行模型降阶。求解降阶后系统状态方程并确定系统惯性中心频率的表达式,进而计算扰动后系统频率的最低值。与PSS/E的仿真结果进行比较,该算法能够准确、快速计算扰动后系统频率的最低值。使用扰动后25ms及50ms时的系统广域量测数据,该算法仍能准确计算出系统频率最低值,表明该算法对系统的广域量测数据具有一定的鲁棒性。该算法能够用于电力系统频率安全稳定的在线评估。(4)频率稳定自动切负荷控制算法。提出了一种对扰动后系统频率最低值进行控制的自动切负荷算法。假设已知系统切负荷总量在切负荷点的分配比例,根据扰动后系统频率最低值的预测结果,预先设定一个初始的切负荷量,建立切负荷后系统的状态方程及输出方程,计算切负荷后系统频率的最低值。比较频率最低值的预测结果与整定值,采用二分法调整系统所需要的切负荷量。通过算例分析,该方法能够快速、准确计算系统所需要的切负荷量。该算法能够用于自动切负荷控制切负荷量的在线整定。
[Abstract]:The power system frequency reflects the balance of the supply and demand of active power in the system. It is an important indicator of the operation of the power system. When the UHV transmission line is out of operation because of the failure, the system disintegration or the large capacity unit may cause a large active vacancy in the system, which will lead to the instability of the system frequency. The frequency dynamic characteristic analysis of force system is the basis of frequency stability analysis and control in power system. The commonly used method of frequency stability analysis of power system is single computer equivalent model method and time domain simulation method. Single machine equivalent model method can not consider the influence of system network, load on system frequency dynamics; time domain simulation method is difficult to calculate. The wide area measurement system monitors the state of the power network in real time and provides a new means for the analysis and control of the power system. Using the wide area measurement data of the system, the paper mainly studies the frequency analysis method of the power system, the frequency safety and stability online assessment, the frequency stability automatic load cutting control and so on. The following are as follows: (1) the dynamic influence of the boiler and auxiliary equipment on the frequency of the power system. The traditional frequency dynamic research method neglects the influence of the boiler and auxiliary machine on the frequency dynamics of the system. On the basis of the system frequency response model, a simple closed loop model including the power plant boiler, the auxiliary machine and the unit control system is established. The frequency dynamics of the power system is studied. The closed loop model is taken into account of the boiler effect and the frequency effect of the auxiliary equipment driven by the plant. The influence of the system boiler and auxiliary equipment on the frequency dynamics of the system under different disturbance power conditions is studied and compared. The influence of the boiler and auxiliary equipment is discussed in the frequency dynamic analysis. 2) frequency dynamic analysis method. A dynamic analysis method of power system frequency based on the wide area measurement data before and after disturbance is proposed. First, the network of the disturbed system is reduced and the contact node of the system is eliminated; then the network equation, load formula, generator motion equation and original motive governor motion of the system are then carried out. The equation of state is linearized and the state equation and output equation of the system after disturbance are established. Using the wide area measurement data of the system before and after the disturbance, the state equation of the system is solved and the frequency of the inertial center of the system after the disturbance is calculated. By comparing with the simulation results of the PSS/E, this method can accurately describe the dynamic characteristics of the system frequency after the disturbance. (3) an online evaluation method for frequency safety and stability. A fast prediction algorithm based on the system wide area measurement data and the Amoldi model reduction method is proposed. The initial transformation of the system state equation and output equation after disturbance is carried out, and the Amoldi model reduction method is used for the primary transformation. The system state equation and the output equation are reduced. The equation of the system is solved and the expression of the system inertia center frequency is determined. Then the minimum system frequency is calculated after the disturbance. Compared with the simulation results of PSS/E, the algorithm can accurately calculate the lowest frequency of the system after disturbance. The system wide area measurement data at 25ms and 50ms can still accurately calculate the lowest frequency of the system, which shows that the algorithm has a certain robustness for the wide area measurement data of the system. The algorithm can be used for the online evaluation of the frequency safety and stability of the power system. (4) the frequency stabilization automatic load control algorithm. An automatic load cutting algorithm which is controlled by the lowest frequency of the post system. Assuming the proportion of the total load in the system is known at the cutting point, the initial load is set in advance according to the prediction result of the lowest system frequency after the disturbance, and the system state equation and the output equation are established after the load cutting, and the system frequency after the load cutting is calculated. The result of the comparison of the lowest frequency of the frequency and the setting value are compared, and a dichotomy is used to adjust the load required by the system. Through an example analysis, the method can quickly and accurately calculate the load required by the system. This algorithm can be used for the on-line setting of the load of the automatic load cutting control.
【学位授予单位】：西南交通大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TM712

【参考文献】