无功补偿对电网暂态电压稳定影响的研究

发布时间：2018-08-07 19:42

【摘要】：电压稳定问题是电力系统稳定性的重要方面，影响电压稳定的因素以及电压稳定与功角稳定的关系是人们长期以来十分关注的重要理论与工程问题，由于实际电网的复杂性，这些问题也呈现出十分复杂的关联关系，需要结合不同电网的具体特点进行系统深入的研究才能得出符合电网实际的结论。本文以湖南电网为工程背景研究电力系统的电压稳定性，重点研究无功补偿对电压稳定的影响。湖南电网位处华中大区电网的末端，是华中电网的大型受端系统。大量仿真分析表明，湖南电网在丰水期小方式下存在比较突出的电压稳定问题。为此，本文在扼要地综述了电力系统稳定问题的分类以及电压稳定研究现状，并系统地阐述了电压稳定分析的数学模型及其主要分析方法的基础上，系统地研究了湖南电网在丰水期小方式下的运行特点。通过对湘南地区三种负荷水平条件下湖南电网丰水期小方式下潮流分布的特点分析以及500kV主干网络不同位置三相短路时的暂态稳定扫描分析，比较全面地掌握了在湖南电网丰水期小方式运行条件下，系统稳定性方面所存在的主要问题。分别采用静态灵敏度和动态轨迹灵敏度分析方法，系统地研究了湖南电网220kV及以上主网的电压先导节点分布。结果表明，，电网的电压先导节点既是正常运行方式下电压水平对无功补偿容量变化最敏感的节点，也是暂态电压稳定的薄弱节点。在此基础上，系统地研究了无功补偿配置以及系统开机方式对暂态电压稳定性的影响。研究表明，对电压敏感性最大的母线配置足够的并联电容器补偿能够有效地改善系统的正常运行电压水平，但是却更容易导致系统暂态电压失稳；总体而言，采用相当的SVC等动态无功补偿容量配置不仅可以满足正常运行条件下的电压水平要求，而且能够显著改善暂态电压稳定水平；系统的开机方式对暂态电压稳定性具有至关重要的影响，一般而言，无论采用并联电容器补偿或是SVC动态无功补偿，适当增加受端电网的开机比例能够显著提高电网的暂态电压稳定性。基于此结论，提出了不同无功补偿方式下，为保证湖南电网暂态电压稳定性所必需的各区域电源的开机容量比例。对于上述研究结论，采用简化后的简单等值系统给出了合理的机理解释。本文的研究工作来源于实际电网的工程性研究课题，其相关结果和结论对于电网规划设计和运行调度具有工程参考价值。
[Abstract]:Voltage stability is an important aspect of power system stability. The factors affecting voltage stability and the relationship between voltage stability and power angle stability are important theoretical and engineering problems that people have paid close attention to for a long time. These problems also show a very complex correlation relationship, which need to be combined with the specific characteristics of different power systems to carry out a systematic and in-depth study in order to reach a conclusion that is in line with the actual situation of the power grid. In this paper, the voltage stability of power system is studied under the background of Hunan Power Grid, and the influence of reactive power compensation on voltage stability is studied. Hunan Power Grid is located at the end of Central China Power Grid, which is a large receiving system of Central China Power Grid. A large number of simulation analyses show that the voltage stability problem of Hunan power network is prominent in the low water period. In this paper, the classification of power system stability problems and the research status of voltage stability are briefly summarized, and the mathematical model of voltage stability analysis and its main analytical methods are expounded systematically in this paper. The operation characteristics of Hunan power grid in low water supply period are systematically studied in this paper. Based on the analysis of the characteristics of power flow distribution under three load levels in Hunan power grid in high water and small mode, and the transient stability scanning analysis of 500kV trunk network with three phase short circuit at different positions, The main problems of system stability under the condition of Hunan power grid running in small way in high water period are comprehensively grasped. Using static sensitivity and dynamic trajectory sensitivity analysis methods, the distribution of voltage pilot nodes in 220kV and above main network of Hunan power network is studied systematically. The results show that the voltage pilot node is not only the most sensitive node of voltage level to the change of reactive power compensation capacity under normal operation mode, but also the weak node of transient voltage stability. On this basis, the effects of reactive power compensation configuration and system start-up mode on transient voltage stability are systematically studied. The results show that the most sensitive bus with enough shunt capacitor compensation can effectively improve the normal operating voltage level of the system, but it is more likely to lead to transient voltage instability of the system. The use of SVC and other dynamic reactive power compensation capacity configuration can not only meet the requirements of voltage level under normal operation conditions, but also can significantly improve the transient voltage stability level. The start-up mode of the system has a vital effect on the transient voltage stability. Generally speaking, whether the shunt capacitor compensation or the SVC dynamic reactive power compensation is used, The transient voltage stability of the power network can be improved by increasing the proportion of the receiver network. Based on this conclusion, the start-up capacity ratio of power supply in different reactive power compensation modes is proposed to ensure the transient voltage stability of Hunan power network. For the above conclusions, the simplified simple equivalent system is used to give a reasonable explanation of the mechanism. The research work in this paper comes from the engineering research subject of actual power network, and its related results and conclusions have engineering reference value for power network planning, design and operation and dispatching.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM712

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