Development of Novel Models and Control Methods for Multilevel-VSC Multiterminal HVDC-Systems for Improving the Stability of Interconnected AC- and DC-Grids

开发多级VSC多端高压直流输电系统新模型和控制方法以提高互联交直流电网的稳定性

• 批准号: 360290054
• 负责人: Professor Dr.-Ing. Matthias Luther
• 金额: --
• 依托单位: Department Elektrotechnik-Elektronik-Informationstechnik
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2020-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/360290054?language=en
• 关键词: Development; Novel; Models; Control; Methods

The suggested work program comprises the development of models of novel multilevel-VSC multiterminal HVDC and the appropriate innovative control concepts in order to give a significant contribution to both the stability of the AC- and DC-grid. Against the background of the German 'Energiewende' the interconnected system is transforming to a hybrid and multimodal energy system. The high penetration of renewable energies, the shut-down of conventional and nuclear power plants, the consequently resulting lack of inertia, the novel hybrid and multimodal structure and the bidirectional flow of energy across all network levels must therefore require a change of the control strategy of the entire energy systems.In order to ensure the stability of the future grid the novel multilevel Voltage-Source-Converter can make a valuable contribution due to the existence of many degrees of freedom in its control. Therefore, the approach of the weighted droop-constants, which applies a frequency droop to the AC-grid and a voltage droop to the DC grid at the same time needs investigation in order to provide the proper method for the selection of the droop constants and weighting factors. Hence, optimization approaches as the Particle Swarm Optimization and the Bacterial Foraging Algorithm will be used since they promise very good results for large scale systems. An implementation of the models in the test and integration environment of the Priority Program is intended in order to compare and validate the results with the other contributors. Since the topology of the multilevel converter allows a decoupling of the AC- and DC-side, the energy stored in the cells of the converter plays a very important role. A power deviation between the AC- and DC-side does not directly influence the DC-voltage, but affects the converter energy. Therefore, the advancement of the voltage droop- to an energy droop-method is carried out. In order to guarantee a proper contribution of the method to the system stability, the optimization approaches have to be applied to the energy droop-method as well.Once the different droop-methods are intensively investigated and deep insights could be gained, the second funding period should focus on nonlinear control approaches. Droop-methods always provide a linear characteristic between active power deviations and frequency, voltage or energy support respectively. But, as the transformation of the energy system is continuously advancing, linear control approaches might not sufficiently fit to the novel topology of the grid anymore. Nonlinear control approaches could therefore gain better stability effects and more sophisticated system service.

建议的工作计划包括新型多级VSC多发HVDC的模型和适当的创新控制概念的发展，以便对AC-和DC-Grid的稳定性做出重大贡献。在德语“ energiewende”的背景下，相互联系的系统正在转换为混合和多模式的能源系统。可再生能源的高渗透率，常规和核电厂的关闭，导致导致缺乏惯性，新型混合和多模式结构以及所有网络范围内的能量的双向流动，因此必须改变整个能源系统的控制策略，以确保将未来的多个成分构成的稳定性，因此可以使多个构成的稳定性能够促进多元的稳定性。自由度在其控制中。因此，加权下垂组构体的接近，该方法将频率下降到交流电网上，并同时需要调查到直流电网上的电压下垂，以便为选择下垂常数和加权因子提供适当的方法。因此，将使用优化方法作为粒子群优化和细菌觅食算法，因为它们对大型系统的效果非常好。优先计划的测试和集成环境中的模型的实现旨在将结果与其他贡献者进行比较和验证。由于多级转换器的拓扑允许将AC和DC侧脱钩，因此存储在转换器细胞中的能量起着非常重要的作用。 AC-和DC侧之间的功率偏差不会直接影响直流电压，而是影响转换器能量。因此，进行了电压下垂到能量下垂方法的进步。为了确保该方法对系统稳定性做出适当的贡献，还必须将优化方法应用于能量下垂方法。一旦对不同的下垂方法进行了深入研究并可以获得深刻的见解，第二个融资期应集中在非线性控制方法上。下垂方法始终在主动功率偏差和频率，电压或能量支持之间提供线性特征。但是，随着能量系统的转换正在不断前进，线性控制方法可能不再足够适合网格的新拓扑。因此，非线性控制方法可以获得更好的稳定性效应和更复杂的系统服务。