【作者】 李维；

【导师】 房大中；

【作者基本信息】 天津大学 ， 电力系统及其自动化， 2010， 硕士

【摘要】 随着现代电力系统的迅速发展,大量高压直流输电系统(High Voltage Direct Current, HVDC)和柔性交流输电装置(Flexible AC Transmission Systems, FACTS)等电力电子设备广泛应用于其中。这些设备的投入使得电力系统的运行和控制更为复杂,同时也对电力系统仿真分析技术提出了更高的要求。HVDC系统和FACTS装置对系统故障具有快速响应能力,目前主要运用电磁暂态仿真程序来研究其在系统暂态过程中电压和电流的快速变化现象。但由于计算机存储和计算能力有限,即使用并行计算方法也难以对大型电力系统进行全网电磁仿真。而机电暂态仿真程序(Transient Simulation Program,TSP)基于元件的准稳态模型,不能反应元件内部的电气量瞬时变化过程。为了弥补以上两点不足,电力系统机电暂态与电磁暂态混合仿真算法对电力电子装置部分进行详细的电磁仿真,以便精确模拟其动态特性;对外部交流系统则进行机电仿真,以加快仿真效率。本文研究的混合仿真算法将TSP程序嵌入到商业电磁暂态仿真软件PSCAD (Power Systems CAD)主程序中,利用PSCAD自带的元件库搭建HVDC系统及其控制模型,并对其进行电磁仿真,同时用TSP程序对外部交流网络进行机电仿真;数据交换通过连接二者的接口母线进行,从而实现全网的数字仿真。该算法考虑了系统故障后频率偏移对电磁暂态仿真精度的影响,动态更新接口母线电压的瞬时频率。混合仿真算法采用戴维南等效电路来代替外部网络对HVDC电磁仿真部分的影响,而将HVDC系统等效为时变恒功率负荷来代替其对外部网络的影响。用基于Kundur 2区域系统的交直流系统对该算法进行了仿真测试,并将其结果与PSCAD的仿真结果比较,验证了本文提出的算法能准确地反应HVDC系统经受扰动后的动态特性。更多还原

【Abstract】 With the rapid development of modern power systems, many high-power electronic devices have been widely applied in them, such as HVDC links and FACTS devices. This has made system operation and control become more complex than ever before, at the same time setting down higher requirements for power system simulation and analysis techniques.HVDC links and FACTS devices, which respond rapidly to system failures, are mainly simulated with electro-magnetic transient program (EMTP) nowadays to study the detailed transients of instantaneous voltages and currents caused by system disturbances. Due to the limitation of computer storage and computation capability, however, it is barely possible to simulate a large power system with EMTP, even with parallel algorithms. On the other hand, transient simulation program (TSP), based on single-phase quasi-steady state models, can provide a large power system simulation with efficiency, but not instantaneous detailed simulation of these electronic devices. In order to overcome the disadvantages of both methods mentioned above, hybrid simulation algorithms have been developed, which implement EMTP simulation for electronic devices to get accurate dynamic characteristics, and TSP simulation for the external AC power system to raise the efficiency.The hybrid simulation algorithm presented in this paper embeds a transient stability program into the main program of commercial electro-magnetic simulation software PSCAD through the user interface. HVDC links and FACTS devices, along with their control systems, are constructed with the component library of PSCAD, and simulated in detail, meanwhile the external AC power system is simulated with TSP; data exchange are implemented through the interface buses at which these two parts interact. The effect of frequency deviation on electro-magnetic simulation caused by system disturbances is considered in this algorithm, the frequencies of the voltages at interface buses are updated dynamically. Thevenin equivalent circuit is used to replace the effect of the external AC power system on HVDC simulation, and the HVDC system is replaced with time-variant constant-power loads in transient stability simulation. Simulative tests for the proposed algorithm are performed on a AC-DC system based on Kundur’s two-area system, and the obtained simulation results are compared with those by PSCAD software, comparison results show that the proposed method can reflect accurately the dynamics of power systems with HVDC links caused by system disturbances.更多还原