Development of methods and models for assessing voltage stability in power systems with a high penetration of power generation from renewable sources

随着从化石能源发电转向可再生能源发电的政治变革，对电力系统安全运行的要求将会越来越高。特别是在德国，风电和光伏发电装机容量达到峰值。根据德国联邦环境部（BMU）的预测，预计风能和光伏的装机容量将分别达到50吉瓦左右。因此，这一装机容量甚至超过了峰值负荷，峰值负荷位于德国，约为80吉瓦。此外，风能和光伏电站集中在风力大、太阳辐射大的地区。结果是，如果天气适宜，未来将出现大型发电中心。与此同时，通常位于负荷中心附近的传统化石发电厂将被可再生能源发电所取代。这导致需要传输的电力以及发电机组和负荷之间的距离急剧增加，因此增加了系统应力。最初，修建输电系统是为了在自治地方之间输送备用电力。随着预期的未来传输功率和距离，电压稳定性将达到极限。因此，除了电网部件的热容量限制外，电压稳定限制可能成为电力系统的关键运行变量。现有的电压稳定性评估模型和方法不适用于表征和评估可再生能源高渗透的变化系统。因此，该项目的目的是开发模型和方法，以评估输电系统和配电系统的电压稳定性，同时考虑到不断变化的可再生能源发电结构。由于可再生能源大多安装在配电系统中，因此本项目的重点之一是建立考虑可再生能源分布式发电的配电系统模型。亚琛工业大学电力系统和电力经济研究所开发了一个欧洲输电网络模型和一个市场模拟，以确定最优的发电厂调度。这将用于获得未来一段时间的真实网络情况。本项目的新模型和方法可以详细分析可再生能源并入电力系统的可能性，同时考虑不同的负荷和调度情况以及不同的网络结构，包括任何网络设备的关键应急情况。

Because of the politically decided revolution to change generation of electric power from fossil to renewable sources requirements for the secure operation of the power system will get intensified. Particularly, in Germany peaks of installed wind and photovoltaic capacities are reached. In prognoses of the German Federal Ministry for the Environment (BMU) around 50 GW of installed capacity each for wind and photovoltaics are expected. Thus, this installed capacity exeeds even the peak load, which is located in Germany in the range of around 80 GW. In addition, wind and photovoltaic power plants concentrate in areas with high-wind and high solar radiation. The result is that in the future centers of large power generation will emerge, if the weather is suitable. At the same time conventional fossil power plants, which are usually placed near load centers, will be replaced by renewable power generation. This results in a dramatic increase of power to be transported as well as distances between power generation and load and therefore in an increased system stress.Originally, the transmission system was built in order to transport reserve power between autonomous areas. With the expected future transport power and distances, voltage stability limits will be reached. Therefore, in addition to the thermal capacity limits of network components voltage stability limits may become the critical operating variable of power systems.The currently existing models and methods for assessing voltage stability are not suitable to represent and to evaluate the changing system with high penetration of renewable energies.The aim of the project is therefore to develop models and methods for assessing voltage stability in transmission system and distribution systems taking into account the evolving renewable generation structure.As renewable energies are mostly installed in distribution systems, one focus of this project is to develop a model of distribution systems with consideration of distributed power generation from renewable energy sources. At the Institute of Power Systems and Power Economics at RWTH Aachen University a model for the European transmission network and a market simulation to determine the optimal power plant dispatch has been developed. This will be used to get realistic network situations for future periods.The new models and methods of this project allow detailed analyses of the possible integration of renewable energies into the power system with consideration of different load and dispatch situations as well as different network structures including critical contingency situations of any network equipments.