基于柔性负荷的孤立多能互补建筑能源系统优化设计

构建基于柔性负荷的多能互补建筑能源系统是解决孤立乡村能源供给问题的有效手段。采用Matlab/Simulink建立孤立多能互补建筑能源系统优化模型,并以系统的费用年值最低为优化目标,基于遗传算法求解计算。研究结果表明,与不考虑柔性负荷相比,柔性电负荷、柔性热负荷、柔性电/热负荷参与调节时,系统的费用年值分别降低了5.24%、33.11%与35.50%。柔性电负荷参与调节后,负荷向光伏出力时段平移,储能电池和柴油发电机的容量得以降低。与仅有柔性热负荷参与调节相比,柔性电、热负荷同时参与调节时,室内温度波动平缓,波动振幅小。     

计及并网强度最大化的新能源集群出力优化研究

随着柔性负荷接入电网的比例不断增多和新能源逐渐向集群化并网发展,如何在柔性负荷剧烈波动和保障电网强度的条件下优化调度新能源集群并网出力,已成为迫切需要解决的问题。文章首先从系统架构、集群化并网特点和短路容量计算方面对新能源集群并网进行了分析,在此基础上给出了新能源集群并网点短路比、广义短路比、运行广义短路比的计算方法;其次分析了近年来激增的柔性负荷分类及特点,研究了柔性负荷接入下的运行广义短路比;最后研究了柔性负荷波动下,以运行广义短路比最大为目标的新能源集群并网出力优化调度方案,并通过算例与传统等比例原则调度方案进行了对比。结果表明,所给方案能够在满足电网功率波动的情况下,保障新能源集群并网强度,实现新能源出力优化分配。     

基于负荷类型细分的负荷聚合商日前投标非合作博弈模型

负荷聚合商能整合中小负荷资源并为其提供参与市场调节的机会,以提高需求响应效率。提出了一种基于负荷类型细分和非合作博弈的负荷聚合商日前投标模型,一方面根据居民柔性负荷的不同用电特性进行典型分类并将每一类负荷作为研究对象,避免了以家庭为控制单位参与投标的复杂度;另一方面在开放电力市场下,不同于常规多目标集中优化,引入博弈思想协调优化各聚合商作为独立决策主体的利益。根据物理特性将居民柔性负荷分成4类,并基于用户使用习惯和舒适度建立负荷模型;在市场电价的引导下,基于用户黏性理论优化聚合商售电电价,建立负荷聚合商日前投标决策模型并进行算例分析。仿真结果表明,所建立的负荷聚合商投标决策模型通过对居民负荷的分类聚合和补偿,在计划调度层面能有效减少电网峰时负荷和平抑峰时电价,提高负荷聚合商的利润,降低用户用电成本。     

考虑用户侧柔性负荷的社区综合能源系统日前优化调度

针对综合能源系统中存在潜在的可调度资源,基于能源集线器构建包含储能、燃气轮机发电系统、柔性负荷等在内的社区综合能源系统数学模型。该模型综合考虑用户侧柔性负荷的可平移、可转移、可削减的负荷特性。最终建立以总运行成本最小为目标的综合能源系统供需联合日前优化调度模型,采用Yalmip工具箱和Cplex求解器对算例进行求解,得到3种场景下柔性电、热负荷参与调度的优化结果,并对比分析电热独立调度的经济效益。仿真结果表明:电热耦合调度,柔性电、热负荷的参与互动能明显降低系统运行成本,减小负荷峰谷差,缓解高峰用电压力。     

空调—电动汽车群需求响应与分布式电源协调优化策略研究

空调和电动汽车等柔性负荷资源具有被纳入系统调度的潜力,通过调节柔性负荷群用电功率可以减轻联络线功率波动,促进可再生能源消纳.基于日前调度,在满足人体舒适度和出行满意度的前提下,提出了同时考虑不同类型负荷聚合商购电成本最小和分布式光伏消纳最大的多目标优化调度模型,以及需求响应的价格补偿策略.采用带加权系数的最短距离理想点法将多目标转化为单目标进行求解.IEEE 33节点系统的算例仿真结果验证了所提模型方法的有效性.     

计及需求响应的综合能源系统协同优化策略

综合能源系统（Integrated Energy System,IES）可以实现多能协同互补、促进能量梯级利用,同时综合需求响应作为柔性负荷的直接调控手段,在提升IES经济与可靠运行方面展现出巨大潜力。文章基于电-气互联系统,综合考虑多元储能系统的运行特征及IES多能耦合特性,构建了IES多能耦合模型;进一步地,将传统电负荷需求响应拓展到IES中,提出了多元负荷的综合需求响应机制;进而以IES系统运行成本最小化为优化目标,建立了计及多元负荷需求响应的IES优化调度模型,并借助商用求解器实现了IES优化模型的高效求解。算例分析验证了所提模型可以充分发挥多元柔性负荷需求的响应潜力,促进可再生能源消纳,同时提高IES运行的经济性。     

考虑柔性负荷的综合能源系统低碳经济优化调度

随着低碳发展进程的不断推进,综合能源系统(IES)逐渐成为实现减排目标的重要支撑技术。基于能源集线器概念,结合需求侧柔性负荷的可平移、可转移、可削减特性,构建了含风光储、燃气轮机、柔性负荷等在内的IES模型。综合考虑了系统运行成本和碳交易成本,建立了以总成本最低为优化目标的IES低碳经济调度模型,采用鲸鱼优化算法对算例进行求解。通过场景对比,分析了碳交易因素对能源调度的影响,以及在碳交易体系之下,柔性负荷的合理调度对IES进一步减少碳排放、降低系统成本可发挥的作用。研究结果表明,在碳交易体系下,柔性负荷参与调度能有效地提高系统的经济环境综合效益。     

考虑柔性负荷的含光伏电力系统模糊随机优化调度风险研究

针对光伏出力和负荷的不确定性,利用柔性负荷削峰填谷、平抑光伏波动,将柔性负荷成本融入调度模型之中,建立考虑柔性负荷的含光伏电力系统模糊随机优化调度模型,并采用改进细菌群体趋药性算法对其进行求解。针对机会约束规划所引起的失负荷风险,建立风险量化指标。算例分析不同模糊随机置信度、不同风险系数对系统运行调度的影响,验证该模型可有效协调系统运行的经济性与风险性、降低系统的运行成本,并提高系统对光伏的消纳能力。     

关中农村不同类型家庭夏季柔性用能负荷多目标优化调度研究

发展农村可再生能源，解决供给随机波动所导致的供需匹配问题至关重要。在经济可行的范围内，现有供需匹配提升作用基本已被发挥至上限，柔性用能负荷调节是从需求侧解决问题的革命性新方法。该文基于关中农村实地调研数据，分析不同类型家庭夏季用能特征，在充分考虑柔性用能负荷的前提下，建立求解以经济性与舒适性为目标的农村家庭柔性用能负荷多目标优化调度模型。结果表明：1）关中农村家庭根据用能特征可分为独居老年家庭（第一类）、三代同堂家庭（第二类）、居家青年家庭（第三类）以及务工青年家庭（第四类）。2）峰谷电价下，第二类家庭负荷调节潜力最大，用电成本削减比例最高为19.5%，不舒适指数增加比例最高为46.3%；第四类家庭负荷调节潜力最小，用电成本削减比例最高为12.3%，不舒适指数增加比例最高为17.8%。3）对于可平移类柔性负荷，第一、二、三类家庭可调节潜力均较大；对于可中断类柔性负荷，第一类家庭可调节潜力最大；对于可削减类柔性负荷，第二类家庭可调节潜力最大。     

基于智能软开关的柔性互联低压配电网优化控制

智能软开关(Soft Open Points,SOP)的普及使得多台区联合运行成为趋势。针对大规模户用光伏接入低压配电网带来的电压越限、网损和三相不平衡问题,提出一种基于SOP的柔性互联两阶段优化控制架构。日前阶段,考虑长时间尺度光伏及负荷功率,建立以台区Ⅰ、Ⅱ总网损最小、三相不平衡度最小为目标函数的三相四线柔性互联低压配电网优化模型,求取SOP三相功率出力,采用模型凸化的方式降低求解难度。日内阶段,针对光伏及负荷5分钟短时功率扰动带来的电压波动越限问题,基于日前SOP优化结果,利用SOP两侧换流器电压-无功下垂控制方法抑制电压越限问题。仿真结果表明,所提两阶段优化控制策略能够有效抑制高比例光伏并网带来的供电质量问题。此外,为了保障优化结果对比分析的客观性,选取与本文优化参数相近、光伏接入情况与网络模型相同的文献案例进行对比分析。分析结果表明,通过功率在空间上的转移,实现不同交流台区间的功率互济,解决了多个台区存在的电压质量和网损问题,并且控制变量数目更少,综合优化结果更好。     

Optimal dispatch of multi energy system using power-to-gas technology considering flexible load on user side

The relation between power-to-gas technology (P2G) and energy interconnection becomes increasingly close. Meanwhile, the participation of flexible load on user side in system optimization has attracted much attention as an efficient approach to relieve the contradiction between energy supply and energy demand. Based on the concept of energy hub, according to its series characteristic, this paper established a generic multi-energy system model using the P2G technology. The characteristic of flexible load on user side was considered and optimal dispatch analysis was made, so as to reduce the cost, to reasonably dispatch the flexible load, to reduce the discharge, to enhance the new energy output, and to increase the power-to-gas conversion efficiency. Finally, a concrete analysis was made on the optimal dispatch result of the multi-energy system using the P2G technology considering flexible load on user side in the calculating example, and optimal dispatch of the system was verified via four different scenarios. The results indicate that cooperative dispatch of multi-energy system using the P2G technology considering flexible load on user side is the most economic, and can make a contribution to absorption of new energy and P2G conversion. In this way, environmental effects and safe and stable operation of the system can be guaranteed.     

Modeling alkaline water electrolysis for power-to-x applications: A scheduling approach

The flexible operation of alkaline water electrolyzers enables power-to-x plants to react efficiently to different energy scenarios. In this work, a novel scheduling model for alkaline water electrolysis is formulated as a mixed-integer linear program. The model is constructed by implementing operational states (production, standby, idle) and transitions (cold/full startup, shutdown) as integer variables, while the power loading and hydrogen flowrate are set as continuous variables. The operational characteristics (load range, startup time, ramp rates) are included as model constraints. The proposed model allows finding optimal number of electrolyzers and production schedules when dealing with large data sets of intermittent energy and electricity price. The optimal solution of the case study shows a balance between hydrogen production, energy absorption, and operation and investment costs. The optimal number of electrolyzers to be installed corresponds to 54% of the ones required to absorb the highest energy peak, being capable of loading 89.7% of the available energy during the year of operation, with an overall plant utilization of 93.7% and 764 startup/shutdown cycles evenly distributed among the units.     

柔性电动汽车和分布式电源的协同优化调度研究

针对电动汽车(EV)接入电网后,出现的负荷"峰上加峰"的问题,在描述传统机组发电特征及调度分布式电源作为补充的基础上,提出了柔性电动汽车与分布式电源协同优化调度方案。该方案考虑4类电动汽车的出行规律及充电方式,同时以发电投资总成本与柔性EV用能成本之和最小作为优化目标,建立车网交互(V2G)的机组组合模型。在考虑柔性EV行驶特性与机组运行特性基础上,将所提模型转化为一个大规模混合整数线性规划(MILP)问题,利用Ipsolve解算器求得最优解以及最优调度方案。文章选取某城市各类电动汽车为研究对象,分析柔性EV用能成本对系统总成本与CO2排放量的影响。仿真结果验证了采用柔性EV与风电协同优化传统机组出力的有效性和考虑柔性EV用能成本的必要性。     

Prospect of new pumped-storage power station

In this paper, a new type of pumped-storage power station with faster response speed, wider regulation range, and better stability is proposed. The operational flexible of the traditional pumped-storage power station can be improved with variable-speed pumped-storage technology. Combined with chemical energy storage, the failure to achieve second-order response speed and the insufficient safety and reliability of pumped-storage power units could be solved. With the better solar energy and site resources, the integrated performance can be improved by an optical storage system installed in future pumped-storage stations. Through the characteristics analysis of the new type of pumped-storage power station, three types of optimal station locations are proposed, namely, the load concentration area, new energy concentration area, and ultra- high-voltage direct current receiver area. Taking the new pumped-storage power station as an example, the advantages of multi-energy cooperation and joint operation are analyzed. It can be predicted that the frequency and load regulation of the power grid will be more flexible, and the service capacity to the main power grid will be much stronger in the future.     

Three‐level energy flexible management strategy for micro energy grids considering multiple uncertainties at different time scales

This paper considers the co‐optimization operation problem of the multiple micro energy grids (MEGs), and proposes a novel concept of the flexible boundary. Then, a three‐level co‐optimization model of reconfiguration, dispatching, and reserve is designed considering different time scales. Furthermore, an improved ant colony algorithm based on the information entropy and the chaotic search is proposed. The Shenzhen international low‐carbon park in China is selected as an example. The results show that: (a) The capacity configuration scheme considering the flexible boundary conditions could decrease the reserve capacity of power, heating, and cooling from the upper energy grid, namely, 75%, 50%, and 75%, and delay 537 × 10⁴¥ the investment cost of the new capacity by utilizing the complementary characteristics between different MEGs. (b) The proposed three‐level co‐optimization model could establish the multi‐level optimal cooperative operation schemes of multi‐MEGs and decrease the reserve power from the upper energy grid and incentive‐based demand response. Among them, UPG provides MEG 1, MEG 2, and MEG 3 with cooling load reserve capacity reduction of 53.95, 85.44, and 38.3 kw h. The positive reserve provided by IBDR for MEG 1, MEG 2, and MEG 3 decreased by 30.53, 20.21, and 52 kW h. (c) The proposed improved ant colony algorithm can consider the operational characteristics of each energy entity in different stages of multi‐MEGs and obtain the global optimal operation scheme. Compared the traditional ant colony algorithm, the average convergence times decrease by 18% and the optimization degree of the objective value increase by 12.38%. (d) The sensitivity analysis shows the conditional value at risk method can formulate the optimal dispatching schemes of multi‐MEGs according to the risk attitudes of decision makers. When confidence degree is between 0.3 and 0.8, the decision‐makers have a high‐risk sensitivity and are more willing to avoid uncertain risks of wind power plant and photovoltaic power. Overall, the proposed model and solution algorithm could achieve the optimal operation strategy of the micro energy grids.     

Optimization modeling method for coal-to-electricity heating load considering differential decisions

Heating by electricity rather than coal is considered one effective way to reduce environmental problems. Thus, the electric heating load is growing rapidly, which may cause undesired problems in distribution grids because of the randomness and dispersed integration of the load. However, the electric heating load may also function as an energy storage system with optimal operational control. Therefore, the optimal modeling of electric heating load characteristics, considering its randomness, is important for grid planning and construction. In this study, the heating loads of distributed residential users in a certain area are modeled based on the Fanger thermal comfort equation and the predicted mean vote thermal comfort index calculation method. Different temperatures are considered while modeling the users’ heating loads. The heat load demand curve is estimated according to the time-varying equation of interior temperature. A multi-objective optimization model for the electric heating load with heat energy storage is then studied considering the demand response (DR), which optimizes economy and the comfort index. A fuzzy decision method is proposed, considering the factors influencing DR behavior. Finally, the validity of the proposed model is verified by simulations. The results show that the proposed model performs better than the traditional method.     

厂级AGC机组负荷优化分配系统研究

针对我国目前电网的调度模式,提出了在自动发电控制(AGC)方式下的厂级负荷优化分配系统实现方案,该方案不改变电厂原有网络结构,直接在厂级监控信息系统中增加负荷控制节点,这样既不改变控制系统原有的各项功能,又使厂级负荷控制的投切比较灵活,大大增强了系统的稳定性。在优化算法上提出了遗传禁忌混合算法,以某电厂的3台机组为例,采用2008年负荷数据进行优化分配,并与实际分配进行对比,结果表明采用该算法进行优化分配后煤耗率下降了0.2g/(kW.h)～5.3g/(kW.h),对电厂节能降耗,提高经济效益有重要意义。     

区域能源规划中站网布置优化设计方法研究与应用

为解决区域能源规划中能源站选址和管网规划的耦合问题,从整体规划角度出发,基于城市规划的功能地块分布特点和用户负荷特性,构建了区域分布式能源系统(Regional Distributed Energy System,RDES)的"站—网"一体化布局模型。提出了基于最小生成树思想的布网选址算法,在遍历解集空间中所有可行解基础上得到确定的最优解,确定了区域内最优的能源站数量、站址和容量以及能源站至负荷点输送管网的最优路径。最后,通过实际工程案例验证了所构建站网布局模型与布网选址的可行性与合理性,为区域能源规划的站网规划提供了理论参考。     

基于热电互动的分布式能源系统优化研究

  [目的]  为实现分布式能源系统经济、高效的为工业用户供能,基于工业园区电、热负荷的耦合特性,建立了分布式能源系统供能单元的性能模型,提出了优化运行策略。  [方法]  以广州某工业园区为研究对象,结合实际负荷数据,合理确定优化参数,计算了年发电量、年耗气量和一次能源利用效率,并对负荷增量的影响进行了研究。  [结果]  结果表明:机组启动热负荷对分布式能源系统的年发电量影响较大,采用优化运行策略,年发电量提升约18.7%,可以提高园区自供电比例,一次能源利用效率在85%以上。  [结论]  该优化运行策略是正确并有效的,可应用于热电耦合分布式能源系统的优化,有效提升分布式能源系统的供能,同时维持较高的一次能源综合利用效率。