【作者】 李岩松；

【导师】 张建华； 雷金勇；

【作者基本信息】 华北电力大学(北京) ， 电气工程（专业学位）， 2016， 硕士

【摘要】 随着全球性节能减排的呼声不断增加,越来越多的国家认识到可再生能源替代化石能源的必要性与紧迫性。微电网凭借其可合理整合可再生能源、发电方式灵活、可脱离电网独立运行、具备储能系统、分布式发电线路损耗小等优点得到了空前的发展。随着微电网的不断增多,其互联运行的优点逐渐凸显,不论是通过电力互用实现时空资源互补,还是提升互联系统整体运行的暂、稳态稳定性,抑或在配电网故障时通过互联扩大供电范围进而实现配电网的黑启动,都体现了微电网互联运行的迫切需求。但是,微电网不能直接互联而不加以管控,因为互联后电源功率分配系数可能不匹配而造成全网发电成本反而升高,得不偿失；此外,两微电网中电源的综合协调控制也面临新的挑战。因此,应通过合理的方式和管理、控制策略将微电网进行互联运行。本文从优化调度和实时控制两个层面,提出了微电网互联的运行控制方法,降低系统总体发电成本,提高运行稳定性。在优化调度层面,基于超短期的风光功率及负荷预测结果,以全系统发电成本最低为目标,提出了考虑资源时空互补特性的互联微电网优化调度方法。针对储能电池充放电循环的不完整性问题,提出了适用于分析短时间段内储能电池等效损耗的发电成本模型。在实时协调控制层面,针对风、光功率的间歇性以及负荷投切的随机性而引起的系统功率波动问题,提出了基于动态下垂控制的联络线定功率控制方法,以联络线功率波动量作为微电网的总控制参考偏差,并基于等发电成本微增率分配这一偏差,得到各可控电源的功率修正量；进而采用动态下垂控制实现输出功率的实时修正,在保证联络线功率恒定的基础上,使功率波动量得到经济合理分配。算例构建了基于MATLAB的典型两微电网互联的优化调度模型和基于PSCAD/EMTDC的元件级两微电网互联系统仿真模型,并分别进行了优化调度计算、可控电源功率修正量计算、实时运行控制仿真的算例验证,验证了所提优化调度方法在促进互联微电网资源互补、降低运行成本方面的作用,实时仿真结果验证了动态下垂控制策略可有效实现联络线定功率控制。更多还原

【Abstract】 As the demand for conserving energy and reducing emissions is going up in the world, more and more countries realize the importance and urgency of renewable energy replacing fossil energy. Micorgrid (MG) have been developted greatly because it’s able to a) integrate renewable resources effectively and flexibly, b) work isolated from the main grid, c) storage energy by batteries, d) reduce power loss by distributed generation. With the development of MGs, the interconnection of them under different scenarios has become a natural requirement. Generally, the interconnection requirement exists in two ways. One is for the service restoration in a self-healing distributed network to improve the dynamic performance when islanding occurs and to extend the range of power supply during the system outages. The other is for those on islands or isolated areas to ensure fuller consumption of renewable energy and higher reliability. But the following problems about interconnected microgrids (IMGs) should be taken into account:a) the output of controllable distributed energy resources (CDERs) is supposed to be reset after interconnected, in case the high costly CDER produces a lot of power while the low costly one produces a little, which is definitely not economical, b) synthetical and real-time control of the CDERs in the IMGs is facing new challenges. A method of jointly optimization of generation scheduling and distributed control of CDERs for interconnected operation of autonomous MGs is proposed in this paper.On the aspect of jointly optimization, taking the minimum generation cost as objective, an optimization model is proposed. As the charge and discharge cycle is usually not complete during the operation of batteries, this paper put forward a method of calculating the generation cost of battery energy storage system operating in a short time. And then on the aspect of real-time controlling, a dynamic droop control strategy is designed for the real-time control of CDERs in each MG, so as to keep the power on tie-line to the optimizing result, guaranteeing the autonomy of MGs. Taking the difference between the actual power on tie-line and the planned value as the control error reference, the equal generation costs increment principle is adopted for the CDERs the share the power. Finally, an optimization example based on MATLAB demonstrates the effectiveness on optimizing resource and reducing the cost of operation. The simulation result based on PSCAD/EMTDC confirms the validity of the proposed dynamic control strategy.更多还原