考虑暂态安全稳定约束的受端电网紧急控制研究

发布时间：2018-11-27 12:50

【摘要】：我国负荷中心与能源资源中心的逆向分布,使得特高压电网建设成为必然,东部地区受端电网特征日益明显。特高压交直流线路或大机组故障等导致大电源失去后,可能威胁受端电网的频率安全性、电压安全性,引发设备过载,造成一系列严重后果。为此需要对考虑暂态安全稳定约束的受端电网紧急控制进行优化,在确保系统安全的前提下,减少负荷损失量。本文主要研究内容包括以下三点:(1)对事件驱动型切负荷(event-driven load shedding,EDLS)进行优化。建立切负荷问题的数学模型,在一个统一框架内考虑暂态频率安全、暂态电压安全和过载问题,提出迭代优化算法:分别利用线性化方法和逐步累加法求解确保暂态频率偏移安全(transient frequency deviation security,TFDS)/暂态电压偏移安全(transient voltage deviation security,TVDS)和消除过载所需切负荷,通过整合迭代对总体切负荷量进行优化。给出算法最优解特点,并指出事件驱动原则更有利于保证系统安全。以IEEE39节点系统验证了算法的有效性。证明在一个框架内对考虑暂态安全和过载进行优化,可减少负荷损失量。(2)协调优化 EDLS 与矫正性线路投切(corrective line switching,CLS)。考虑CLS可在不造成负荷损失的情况下,减轻线路过载,因而协调其与EDLS,以优化受端电网的紧急控制。首先建立了问题的数学模型,综合考虑暂态安全问题与过载问题,协调EDLS与CLS。针对这一非线性、多阶段、混合整数规划(Mixed integer programming,MIP)问题,提出双层迭代算法:内层对EDLS进行优化,外层利用邻域搜索法协调两种控制手段。指出该算法在线应用前景。以改进后的IEEE39节点算例,验证了算法有效性。证明了 EDLS与CLS协调优化,丰富了受端电网紧急控制的手段,可减少负荷损失量。(3)设计开发受端电网紧急控制优化程序。根据模块化思想,设计该程序主要包含三个功能:暂态安全稳定定量评估(含暂态频率安全量化评估、暂态电压安全量化评估和暂态功角稳定性评估的实现)、EDLS优化、EDLS与CLS协调优化。EDLS优化模块采用第二章迭代算法,给出其程序流程图;在此基础上,采用第三章双层迭代算法,开发EDLS与CLS协调优化模块。分别以IEEE39节点算例、某省级电网算例和改进后的省级电网算例验证各模块的有效性,证明所开发程序可指导优化考虑暂态安全稳定约束的受端电网紧急控制决策。
[Abstract]:The reverse distribution of load center and energy resource center makes the construction of UHV power grid inevitable. The failure of UHV AC / DC line or large unit may threaten the safety of frequency and voltage of the receiving network and cause the overload of the equipment, which may result in a series of serious consequences. Therefore, it is necessary to optimize the emergency control of the receiving power network considering the transient security and stability constraints, and to reduce the load loss under the premise of ensuring the safety of the system. The main contents of this paper are as follows: (1) optimizing event-driven load cutting (event-driven load shedding,EDLS). The mathematical model of load shedding problem is established, and the transient frequency security, transient voltage security and overload problem are considered in a unified framework. An iterative optimization algorithm is proposed: the linearization method and the stepwise accumulation method are used to solve the problem of ensuring the safety of transient frequency migration (transient frequency deviation security,TFDS) / transient voltage migration (transient voltage deviation security,TVDS) and eliminating the load shedding required by overload, respectively. The overall load shedding is optimized by integrated iteration. The characteristics of the optimal solution of the algorithm are given, and the event-driven principle is pointed out to ensure the security of the system. The effectiveness of the algorithm is verified by IEEE39 node system. It is proved that the load loss can be reduced by optimizing the transient safety and overload in a frame. (2) the optimal EDLS is coordinated with the rectifying line switching (corrective line switching,CLS). Considering that CLS can reduce line overload without causing load loss, it can coordinate with EDLS, to optimize emergency control of terminal power network. Firstly, the mathematical model of the problem is established, and the transient security problem and overload problem are considered synthetically, and the EDLS and CLS. are coordinated. For this nonlinear, multi-stage, mixed integer programming (Mixed integer programming,MIP) problem, a two-layer iterative algorithm is proposed: the inner layer optimizes the EDLS and the outer layer coordinates the two control methods using the neighborhood search method. The prospect of online application of this algorithm is pointed out. The effectiveness of the proposed algorithm is verified by an improved IEEE39 node example. It is proved that the coordinated optimization of EDLS and CLS enriches the means of emergency control and reduces the load loss. (3) the optimization program of emergency control is designed and developed. According to the modularization idea, the program consists of three main functions: quantitative evaluation of transient security stability (including quantitative evaluation of transient frequency security, quantitative evaluation of transient voltage security, and realization of), EDLS optimization of transient power angle stability evaluation). EDLS and CLS coordinate optimization. Chapter 2 iterative algorithm is used in EDLS optimization module, and its program flow chart is given. On this basis, the optimization module of coordination between EDLS and CLS is developed by using the double level iterative algorithm in Chapter 3. The validity of each module is verified by IEEE39 node example, a provincial power network example and an improved provincial power network example, respectively. It is proved that the developed program can be used to guide the emergency control decision of the terminal power network with optimal consideration of transient security and stability constraints.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM712.12

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