交直流混联受端电网暂态电压稳定研究

发布时间：2018-03-15 09:07

本文选题：交直流混联电网　切入点：暂态电压稳定　出处：《华北电力大学》2014年硕士论文　论文类型：学位论文

【摘要】：电压稳定是电力系统安全稳定运行的基础，随着高压直流输电(HVDC)技术的快速发展，我国多个地区电网出现了交直流混联系统，直流输电增加了系统运行方式的灵活性并且扩大了输送容量，同时也使系统结构变得更为复杂，且受端系统往往运行在重载方式下，这些因素导致电压不稳定或电压崩溃引起的局部损失负荷或大面积停电事故呈现增长的趋势。本文在对电力系统暂态电压稳定研究方法综述的基础上，指出目前还没有得到公认的理论严谨的暂态电压失稳判别方法和判别指标，工程上暂态电压稳定的判别目前多采用经验性的方法和判据。第一，通过对实际电网暂态电压失稳事故过程和特征的分析归纳，依据否有短路故障冲击、是否造成大范围潮流转移、是否有交直流耦合问题等特征，对交直流混联系统电压失稳事故进行了分类，为针对性进行暂态电压失稳事故识别和稳控措施实时奠定了基础；通过对简单交直流混联小系统的静态、暂态电压稳定极限的对比，提出对于不考虑短路故障冲击的直流闭锁故障可能引发的电压失稳事故，在一定条件下可采用合理的静态电压稳定极限方法近似逼近暂态电压稳定极限；第二，提出了综合考虑有功、无功传输影响的电压稳定在线评估指标LPQ，既可以快速有效判断系统的静态电压稳定水平，在采用工程实用暂态电压稳定判据的情况下LPQ指标也可用于计算无短路冲击故障引起的暂态电压稳定水平；提出了适用于电力系统稳定分析的电压稳定裕度指标APM及RPM，依据联络通道当前有功、无功潮流及线路送端电压就可以判断系统稳定裕度；在上述研究基础上，梳理提出了在线电压稳定评估体系，依据故障性质不同采用不同的电压稳定判别方法，既有助于简化计算规模、提升在线计算速度，同时也进一步加深了对电压稳定问题的认识，，为进一步研究安全稳定控制措施提供参考。实际交直流混联系统仿真算例表明，利用综合考虑有功、无功潮流传输的电压稳定指标LPQ可以较好的实现对第一类失稳故障下系统暂态电压稳定风险的判断，对系统预防电压失稳及安全稳定控制措施的实施具有重要意义。
[Abstract]:Voltage stability is the basis for the safe and stable operation of power system. With the rapid development of HVDC technology, AC / DC hybrid systems have appeared in many power networks in China. Direct current transmission not only increases the flexibility of the system operation mode, but also increases the transmission capacity. At the same time, it also makes the system structure more complex, and the receiving end system often runs under the heavy load mode. These factors lead to the increasing trend of local loss load or large area blackout caused by voltage instability or voltage collapse. Based on the summarization of the research methods of transient voltage stability in power system, this paper points out that there are no universally accepted methods and criteria for judging transient voltage instability. At present, empirical methods and criteria are used to judge transient voltage stability in engineering. Firstly, through the analysis of the process and characteristics of transient voltage instability accidents in actual power network, according to whether there are short circuit faults or not, This paper classifies voltage instability accidents in AC / DC hybrid system, which lays a foundation for identifying transient voltage instability accidents and controlling them in real time. By comparing the static and transient voltage stability limits of a simple AC / DC hybrid small system, the voltage instability accident caused by DC latching failure without considering the impact of short circuit fault is proposed. Under certain conditions, a reasonable static voltage stability limit method can be used to approximate the transient voltage stability limit. The on-line evaluation index of voltage stability, LPQ, which is influenced by reactive power transmission, can judge the static voltage stability level of the system quickly and effectively. The LPQ index can also be used to calculate the transient voltage stability level caused by the non-short-circuit impact fault, when the engineering practical transient voltage stability criterion is adopted. The voltage stability margin index APM and RPMsuitable for power system stability analysis are proposed. The system stability margin can be judged according to the current active power of the contact channel, reactive power flow and line terminal voltage. In this paper, an on-line voltage stability evaluation system is put forward. According to the fault properties, different voltage stability discrimination methods are adopted, which is helpful to simplify the calculation scale and improve the on-line calculation speed. At the same time, it also deepens the understanding of the voltage stability problem, and provides a reference for further research on the safety and stability control measures. The simulation example of the actual AC / DC hybrid system shows that the active power is taken into account synthetically. The voltage stability index (LPQ) of reactive power flow transmission can be used to judge the risk of transient voltage stability of the system under the first kind of unstable fault. It is of great significance to prevent voltage instability and implement the safety and stability control measures.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM712

【相似文献】