【作者】 王春成；

【导师】 余贻鑫；

【作者基本信息】 天津大学 ， 电力系统及其自动化， 2007， 硕士

【摘要】 随着高压直流输电技术在我国的广泛应用和快速发展,我国电网最终将形成大区域交直流互联的结构。在这种结构下,交/直流系统间的相互作用使得系统的电压稳定问题更加突出。传统的动态安全评估方法是“逐点法”,它虽然是电力系统分析的基本方法,但也存在诸多不足。新近动态安全域方法的研究结果已显示出其在安全性监视、评估与控制决策方面具有逐点法所不具备的多方面的优越性,从而受到了人们更多的关注。正是基于上述原因,本文对保证交直流并联系统大扰动短期电压稳定性的实用动态安全域(Practical Dynamic Security Regions,缩写为PDSR)的性质进行了研究。通过对典型交直流并联输电系统的仿真研究发现:在给定事故、直流功率及控制方式下,在发电机节点有功功率和电压幅值、负荷节点有功功率和无功功率以及直流传输有功功率的决策空间上,交直流并联输电系统的保证大扰动短期电压稳定性的PDSR在较大范围内仍可用(由描述各节点注入功率上、下限约束的垂直于坐标轴的超平面,极少数几个分别对应于不同失稳模态的描述大扰动短期电压稳定性临界点的近似超平面和平衡机节点所对应的约束超平面围成的)超多面体近似描述;在直流输电系统采用整流侧定电流/逆变侧定电压控制方式下,保证系统的大扰动短期电压稳定性的PDSR将扩大;当直流输电控制系统中的依从于电压的电流指令限制环节的参数VL值较大时,保证系统的大扰动短期电压稳定性的PDSR将扩大且具有近似平移性;随直流传输功率的不同、直流定功率控制(传输功率值不变)测控点选择不同和感应电动机占负荷比例的不同,PDSR的临界超平面分别具有各自的近似平移性。这些发现完善了PDSR的已有研究成果,为其实用化奠定了良好的基础。更多还原

【Abstract】 With the increased use of HVDC transmission systems in power systems, the framework of interprovincial AC/DC parallel system has come into practice. It has been found that the interaction between the parallel AC transmission system and the HVDC transmission lines in such configurations is very important to voltage stability of power systems under this framework.The traditional“point wise”approach is one of the most basic approach in the study of power systems analysis. But it also has a lot of deficiencies. Compared with traditional“point wise”approach, the dynamic security regions (DSR) concept is gradually being accepted by electrical power engineers for its advantages on dynamic security monitoring, assessment and optimal control of power systems.The paper mainly studys practical dynamic security regions (PDSR) of AC/DC parallel systems corresponding to short-term voltage stability after a large disturbance.The study on PDSR of the typical AC/DC parallel systems shows the short-term voltage stability PDSR can be surrounded by the vertical hyper-planes which are the upper and lower limits of every bus injection, one or several critical hyper-planes that describe approximately critical points of short-term voltage stability in injection space, and restriction planes of balance node, when the fault, the DC power and the convertor’s control mode are given. It is validated that short-term voltage stability PDSR will expand, when CC/CV control mode and high VL of VDCOL (voltage dependent current order limiter) are adopted. In addition, the critical hyper-planes corresponding to different HVDC power, different power measuring sites with same value and different induction-motor proportion in load are approximately parallel for the same fault, the same unstable mode and the same convertor’s control mode. The discovery improves the results of PDSR study.更多还原