【作者】 陈晖；

【导师】 陈中；

【作者基本信息】 东南大学 ， 电气工程， 2018， 硕士

【摘要】 随着电网中直流输电工程投运量的增加,交直流混联电网呈现出与交流电网相比不同的运行特性。如何有效地评估交直流系统的安全性、发现系统中存在的薄弱环节、采取合适的安全控制措施,对电网的安全经济运行尤其重要。静态安全域为满足潮流方程组和系统中各电气量运行约束的各控制量和各扰动量的集合。静态安全域能从全局角度得到系统的安全信息反馈,在电网的安全监视和安全控制上具有优越性。本文对交直流混联电网静态安全域及协调控制开展研究,主要工作如下:1.建立了交流系统、电网换相换流器(Line Commutated Converter,LCC)直流输电系统和电压源型换流器(Voltage Sourced Converter,VSC)直流输电系统的准稳态模型,对系统中各项运行约束进行分析,以此为基础完成了交直流系统静态安全域的定义、几何描述与方程组定性描述,从而将静态安全域的研究领域由纯交流系统拓展至交直流混联系统。2.在交直流系统静态安全域模型和定义的基础上,研究了若干种静态安全域求解与刻画方法,包括有效边界面筛查、边界距离和运行裕度的计算、边界面表达式拟合求解与检验、基于拟合结果的修正距离计算及计算公式物理意义分析、边界距离概率安全分析、逐点法断面精确描绘与验证等方法,提炼了各方法不同的优缺点以及适用于不同场合的结论。3.完成了LCC直流输电的引入、LCC直流不同控制方式和运行方式、LCC直流参与潮流调控、VSC直流输电的引入、VSC直流参与潮流调控等对系统静态安全域的影响分析,并归纳了直流输电对系统静态安全域边界演变的影响规律。4.在静态安全域的理论研究基础上,利用静态安全域的优势,完成了交直流系统协调控制的应用研究,主要内容包括基于变换后静态安全域的交直流协调校正控制和预防控制的定量计算、基于静态安全域断面的协调控制定性判断、基于计及运行目标的静态安全域的经济运行控制和基于计及控制设备时间特性的带时间轴的静态安全域的协调控制。更多还原

【Abstract】 With the increase of the amount of direct current transmission in the power grid,the AC/DC hybrid power grid shows different operation characteristics compared with the AC power grid.How to effectively evaluate the security of AC/DC system,find out the weak links in the system,and take appropriate security control measures is particularly important for the safe and economic operation of the power grid.The steady-state security region is the set of the control quantities and the disturbance quantities which satisfy the power flow equations and all constraints of all electrical quantities in the system.The steady-state security region can get the feedback of the system’s security information from a global perspective,and has advantages in the security monitoring and security control of the power grid.In this paper,the steady-state security region and coordinated control of AC/DC hybrid power grid will be studied,and the main work is as follows:1.The quasi steady-state models of AC system,LCC-HVDC(Line Commutated Converter-High Voltage Direct Current)transmission system and VSC-HVDC(Voltage Sourced Converter-High Voltage Direct Current)transmission system are built.And a analysis about each operation constraint in system is presented.Based on them,the definition,the geometric description and the qualitative description of equations of steady-state security region of AC/DC power system are completed respectively,so the research field of steady-state security region is extended from pure AC system to AC/DC hybrid system.2.Based on the models and the definition of steady-state security region of AC/DC system,some kind of solution and characterization methods of steady-state security region are studied,including effective boundaries screening,boundaries distances and operation margin calculation,fitting solution of boundaries expressions and fitting testing,corrected distances calculation and physical meaning analysis of calculation formulas based on the fitting results,probabilistic secutity analysis of the boundaries distances,accurate portrayal and verification of cross section by point-to-point method,etc.The conclusions of the advantages and disadvantages of these methods and their applications are refined.3.The analysis of introduction of LCC-HVDC,different control modes and operation modes of LCC-HVDC,power flow regulation participated by LCC-HVDC,introduction of VSC-HVDC,power flow regulation participated by VSC-HVDC influences on the steady-state security region are completed respectively.And influence laws of the DC transmission influences on boundaries evolution of steady-state security region of power system are summarized.4.Based on the theoretical researches of steady-state security region,the application research on coordinated control of AC/DC system is studied using the advantages of steady-state security region.The main contents include quantitative calculation of coordinated correction control and coordinated preventive control based on the transformed steady-state security region,qualitative judgment of coordinated control based on the cross sections of steady-state security region,economic operation control based on the steady-state security region considered operation targets,and coordinated control based on the steady-state security region with time axis considered time characteristics of control equipments.更多还原