混合储能辅助机组参与调频的优化控制与容量配置

发布时间：2018-11-25 16:12

【摘要】：随着科技进步和经济高速发展,电网规模也在不断扩大,国民生产对电力系统频率稳定的要求逐渐提高。同时,为了应对环境污染和化石能源枯竭等问题,具有间歇性和波动性功率输出特性的可再生能源大量并网运行,对电网的频率稳定造成较大冲击。传统机组的调频容量、调频效果和调频成本越来越不能满足当前电网发展的需求。在此背景下,如何在大互联电力系统及可再生能源高渗透并网条件下保持电网频率稳定已经成为目前研究的热点。储能系统具有的快速、精确、瞬时吞吐量大的功率充放特点,能够较好地满足电网的调频需求。将储能系统引入调频领域参与频率调节具有一定的理论意义和现实意义。因此,有必要对储能系统参与系统调频的控制策略、充放电策略和容量优化配置进行研究分析。论文在总结本领域研究现状的基础上,提出将储能系统引入发电侧,与传统机组协调配合共同参与频率调节,该方式可充分利用原有火电机组的调频能力,同时兼顾储能系统的昂贵成本,有效限制储能系统的容量。为此,论文主要完成了以下四方面的工作：首先,对机组进行频率调节的原理进行简要概述,并分析机组投入一、二次调频对机组本身运行的影响；对不同储能系统的经济性能参数对比分析,并确定以铅酸电池(Valve Regulated Lead Acid, VRLA)和全钒液流电池(Vanadium Redox Flow Battery, VRB)组成的混合储能系统；给出储能系统的数学模型,并对控制框图进行了推导分析。其次,对传统机组在一次调频中出现的汽门反向调节现象进行分析,并提出一种新的储能系统控制策略用于消除汽门反调现象；建立控制策略的传递函数并进行分析；通过仿真算例验证,表明该控制策略可以较好地抑制一次调频的反调现象。再次,以单机组参与自动发电控制(Automatic Generation Control, AGC)过程为研究对象,综合考虑混合储能系统的运行特点和传统机组的调频特点,提出储能系统运行的正常场景和四种特殊场景(机组反向调节、机组出力死区振荡、储能系统过充过放和储能系统荷电状态越限),并针对不同场景建立相应的充放电策略。通过实际运行数据进行算例分析,结果表明本文提出的储能系统充放电策略可以较好的响应调度中心下发的AGC指令,提高调频效果。最后,针对混合储能辅助机组参与AGC的容量优化问题,构建了考虑发电厂辅助服务补偿指标的储能系统容量优化计算模型。该模型综合考虑储能系统投资、维护成本和参与AGC调节补偿收益的制约关系,引入KP指标(AGC调频性能指标)、储能系统投资函数和惩罚函数,确立了以发电机组盈利最大为目标的优化函数,进而确定储能系统的最优容量。通过实际运行数据进行算例分析,结果表明本文提出的优化模型可以确定储能系统的最优容量,实现储能系统经济参与调频服务。
[Abstract]:With the development of science and technology and the rapid development of economy, the scale of power grid is expanding, and the requirement of power system frequency stability is raised gradually. At the same time, in order to deal with environmental pollution and fossil energy depletion, renewable energy with intermittent and fluctuating power output characteristics is connected to the grid, which has a great impact on the frequency stability of power grid. The FM capacity, FM effect and FM cost of traditional units can not meet the needs of the current power grid development. In this context, how to maintain the frequency stability of the power network under the condition of large interconnected power system and high permeable renewable energy grid has become a hot topic at present. The energy storage system has the characteristics of fast, accurate and high instantaneous throughput, which can meet the demand of power grid frequency modulation. It is of theoretical and practical significance to introduce the energy storage system into the field of FM and to participate in frequency regulation. Therefore, it is necessary to study and analyze the control strategy, charge and discharge strategy and capacity optimization of energy storage system. On the basis of summarizing the present situation of the research in this field, this paper proposes to introduce the energy storage system into the generating side and coordinate with the traditional units to participate in the frequency regulation, which can make full use of the frequency modulation capability of the original thermal power units. At the same time, the high cost of energy storage system is taken into account, and the capacity of energy storage system is effectively limited. For this reason, this paper mainly completes the following four aspects of work: first, the principle of frequency regulation of the unit is briefly summarized, and the influence of the first and second frequency modulation on the operation of the unit is analyzed. The economic performance parameters of different energy storage systems are compared and analyzed, and a hybrid energy storage system composed of lead acid battery (Valve Regulated Lead Acid, VRLA) and total vanadium liquid flow battery (Vanadium Redox Flow Battery, VRB) is determined. The mathematical model of energy storage system is given, and the control block diagram is deduced and analyzed. Secondly, the phenomenon of valve reverse regulation in primary frequency modulation of traditional units is analyzed, and a new control strategy of energy storage system is proposed to eliminate valve reverse regulation, and the transfer function of control strategy is established and analyzed. The simulation results show that the control strategy can effectively suppress the reverse modulation of primary frequency modulation. Thirdly, taking the single unit participating in the (Automatic Generation Control, AGC) process of automatic generation control as the research object, considering the operation characteristics of the hybrid energy storage system and the frequency modulation characteristics of the traditional unit, In this paper, the normal and four special scenarios of energy storage system (unit reverse regulation, unit output dead zone oscillation, overcharge and release of energy storage system and charging state of energy storage system over limit) are proposed, and the corresponding charging and discharging strategies are established for different scenarios. The results show that the charging and discharging strategy proposed in this paper can better respond to the AGC instructions issued by the dispatching center and improve the FM effect. Finally, aiming at the capacity optimization problem of hybrid energy storage auxiliary units participating in AGC, the capacity optimization model of energy storage system considering the compensation index of auxiliary service in power plant is constructed. The model considers the restriction relation of energy storage system investment, maintenance cost and participating in AGC regulation compensation income, and introduces KP index (AGC frequency modulation performance index), energy storage system investment function and penalty function. The optimal capacity of energy storage system is determined by establishing the optimization function aiming at the maximum profit of generator set. The results show that the proposed optimization model can determine the optimal capacity of energy storage system and realize the economic participation of the energy storage system in FM service.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TM73;TM76

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