微电网中的线路阻抗测量方法研究

微网是解决大规模分布式发电并网的有效方法,微网中逆变器的功率均分及微网系统的建模及稳定性分析是目前的研究热点。要实现微网逆变器功率均分控制和建立微网系统精确模型,微网中馈线阻抗是不可缺少的重要参数,现有多种线路阻抗实时测量方法基本是基于分布式发电或者大电力系统应用考虑,在微电网中应用受到限制。分析了现有的阻抗测量方法的优缺点,针对现有线路阻抗测量技术存在的不足和应用场合限制,提出一种基于MGCC协调控制的,适用于微网中应用的线路阻抗测量方法。文章针对所提的测量方法进行了理论分析和仿真验证,证明了所提方案的可行性。     

Integration of a hybrid fuel cell-battery system to a distribution grid

In order to integrate a proton exchange membrane type (PEM) fuel cell system (FCS) combined with a battery bank to a distribution grid; this paper proposes a local controller based on fuzzy logic. The proposed system provides primary frequency control and local bus voltage support to the local grid. This opposes the passive distributed generation of the present that do not provide auxiliary services, such as back-up power, voltage support and reliability of supply as they operate under constant power factor equal to 1 at all times. During network disturbances, the distributed generations of the present are disconnected until normal operation is reestablished. When the distributed generation penetration is high this may lead to system instability. The microgrid concept is the effective solution for the control and quality improvement of grids with high level of DG penetration. So, the proposed system, also, can be an active controllable microsource of a microgrid in the future that cooperates with other microsources in order to cover the local load demands for active and reactive power either under grid-connected mode or under islanding operating mode. In cases where the distribution grid (working as microgrid) is forced to operate in islanded mode, the hybrid system provides the demanded active and reactive power. The FCS is connected to a weak distribution grid so that the system performance is studied under the worst conditions. The simulation results are obtained using MATLAB software under a severe step load change where the grid is still connected and under islanded operation. In both cases the system presents a good performance.     

IEC61850标准在微电网中的应用探讨

微电网是解决电力系统发展过程中的众多问题而产生的新兴概念。IEC61850是为了解决不同制造商制造的电力设备(尤其是变电站中的设备)集成到一个系统中不能互操作的问题而制定的一个新的通信标准体系。本文提出未来智能电网中一种新的组织单元——智能微电网。数字化变电站根据IEC61850标准分为变电站层、间隔层和过程层。本文基于微电网的三层控制和数字化变电站的三层结构,探讨了IEC61850通信在智能微电网中的应用。     

微网能量管理系统实时数字仿真测试平台研究

为了全面测试微网能量管理系统,在深入了解微网系统组成结构、微源控制方法和高级应用控制策略的基础上,对微网系统实时数字仿真(RTDS)测试平台关键技术进行了研究.技术难点在于微网系统测试平台的搭建方案、接口设计和微网电源建模.研究和实验结果表明:所搭建的模型和平台能够反映微网系统的实时控制特性,满足各种不同微网结构的测试要求,可系统地考核微网能量管理系统,为实际微网系统中的研究和工程实施提供测试数据和理论指导.