【作者】 李胜；

【导师】 张建华；

【作者基本信息】 华北电力大学（北京） ， 电力系统及其自动化， 2009， 博士

【摘要】 城市负荷的持续快速增长及其对供电可靠性要求的不断提高,使得向城市供给大量优质可靠的电能面临着越来越大的困难和挑战。面对危害巨大的灾难性大停电事件,以微网技术为代表的分布式发电系统成为提高供电可靠性的有效手段,是城市电网的有益补充。柔性直流技术的出现为城市高压电网的构建及微电网接入大电网提拱了新的技术手段和解决方案,因此研究柔性直流技术在城市电网中的应用具有重要意义。本文分析了城市电网作为电力系统负荷中心的特点,从高压和中低压两个层次研究了柔性直流技术在城市电网中的应用:建立了两电平和基于开关函数的三电平电压源换流器的数学模型,设计了电压源换流器的多目标解耦控制器;基于RTDS仿真平台建立了三电平柔性直流仿真系统,并对其分别进行了两端有源系统互联和向无源系统供电的仿真研究,所建立的系统具有良好的潮流控制能力和功率反转能力;利用PSS/E分别对算例系统和实际的典型大城市电网仿真系统,验证了VSC DC在提升系统暂态稳定性、降低系统短路水平、增强阻尼以抑制低频振荡及提供无功电压支撑改善系统电压稳定性的能力;把模糊控制技术应用到柔性直流的阻尼低频振荡控制中,通过PSCAD的仿真研究证明了提高系统阻尼的有效性和对不同扰动场景的适应性;研究了柔性直流线路在作为系统分区联络线的情况下,发生局部分区大停电后,基于柔性直流软启动控制的黑启动及系统恢复方案;与传统黑启动方式相对比表明柔性直流技术在快速恢复系统过程中的优越性能;提出了基于柔性直流技术实现城市电网的全过程控制理念;提出了基于柔性直流的微网接入主网的方式,分析了柔性直流技术的微网接入主网方式相对于直接交流接入和通过电流源换流器接入的优点。本文从静态、动态、控制和黑启动多方面论证了柔性直流技术在城市电网中应用的优越性能,对柔性直流技术在城市高压电网和中低压电网的实际应用起到了指导作用。更多还原

【Abstract】 Due to the sustained rapid growth of city load and the continuous increasing demand for safe and reliable power supply,urban power supply with high quality and reliability is facing more and more difficulties and challenges.For the catastrophic blackouts,the newly emerging microgrid technology is a beneficial complement for urban power network and has become an effective means for improving power supply reliability. VSC DC provides a new technical method for the construction of urban high voltage power network,and also provides a solution for the access of micro grid to large power grid.So,it is of great significance to study on the application of VSC-HVDC on urban power network.In this paper,the characteristic of city load center is analyzed and the application of VSC-HVDC on urban power network is studied from high voltage level and middle voltage level:two level model and a mathematical model for three-phase voltage source inverter based on switching function are built,and a multi-objective decoupling controller for voltage source inverter is designed:three level VSC DC simulation system with good controllability of power flow and power reverse is built based on RTDS;the example of test system and the real typical simulation system of urban power network are built using PSS/E software,based on which the ability of VSC DC to improve transient stability,the ability to reinforce damping and suppress low-frequency oscillation,and the ability to provide reactive power support so as to improve system voltage stability are all verified;fuzzy control technology is adopted in the control of damping low-frequency oscillation,its effectively and adaptability of damping are proved through PSCAD software;for the power network with VSC-HVDC as tie line, the VSC DC and soft start control based black start and restoration scheme after black out is studied and compared with traditional black start, and the VSC DC based soft start control has great superiority;the idea of whole process control for urban power network is put forward;the access mode of micro grid to large power grid based on VSC DC is proposed, and its advantages over alternating current access and access through CSC are illustrated.The excellent qualities of VSC DC’s application on urban power network are demonstrated from various aspects in this paper,thus provides important reference value for future practical application of VSC DC in urban high voltage and middle voltage power network.更多还原