Peak Shaving Strategy of Concentrating Solar Power Generation Based on Multi-Time-Scale and Considering Demand Response

According to the multi-time-scale characteristics of power generation and demand-side response(DR)resources,as well as the improvement of prediction accuracy along with the approaching operating point,a rolling peak shaving optimization model consisting of three different time scales has been proposed.The proposed peak shaving optimization model considers not only the generation resources of two different response speeds but also the two different DR resources and determines each unit combination,generation power,and demand response strategy on different time scales so as to participate in the peaking of the power system by taking full advantage of the fast response characteristics of the concentrating solar power(CSP).At the same time,in order to improve the accuracy of the scheduling results,the combination of the day-ahead peak shaving phase with scenario-based stochastic programming can further reduce the influence of wind power prediction errors on scheduling results.The testing results have shown that by optimizing the allocation of scheduling resources in each phase,it can effectively reduce the number of starts and stops of thermal power units and improve the economic efficiency of system operation.The spinning reserve capacity is reduced,and the effectiveness of the peak shaving strategy is verified.

Combined hybrid energy storage system and transmission grid model for peak shaving based on time series operation simulation

This study proposes a combined hybrid energy storage system(HESS) and transmission grid(TG) model, and a corresponding time series operation simulation(TSOS) model is established to relieve the peak-shaving pressure of power systems under the integration of renewable energy. First, a linear model for the optimal operation of the HESS is established, which considers the different power-efficiency characteristics of the pumped storage system, electrochemical storage system, and a new type of liquid compressed air energy storage. Second, a TSOS simulation model for peak shaving is built to maximize the power entering the grid from the wind farms and HESS. Based on the proposed model, this study considers the transmission capacity of a TG. By adding the power-flow constraints of the TG, a TSOS-based HESS and TG combination model for peak shaving is established. Finally, the improved IEEE-39 and IEEE-118 bus systems were considered as examples to verify the effectiveness and feasibility of the proposed model.

Analysis of the Performance Indicators of the PV Power System

The energy assessment of the PV power systems is carried out by using different types of performance indicators that benchmark the output of these systems against the PV panel maximum output at hypothetical operation conditions. In this paper, a comparative analysis of six types of performance indicators is conducted and a new performance indicator which considers PV panel slope and orientation is proposed. The proposed indicator is benchmarking the PV system actual output against the maximum output of the same system if it would operate in two axis tracking mode. The proposed performance indicator is used to develop a friendly user calculator of PV system output that can be used by, energy providers and PV system installers to evaluate the output of the PV grid connect network. The advantage of the developed calculator is high-lighted by a case study that estimates energy capacity of different residential rooftop PV systems installed in a residential suburb in Sydney.

Assessment on Fault Diagnosis and State Evaluation of New Power Grid:AReview

1 Introduction The proposal of the concept of“New Power System”aims to illustrate the transform direction of the traditional power system,acting as the development core of the future new power grid.To achieve this,the proposed strategic targets of“carbon neutralization and carbon peaking”must be implemented and insisted[1].The core feature of the new power system is that renewable energy plays a leading role and becomes the main source of energy supply,meanwhile,the goal of green energy utilization has also been put forward on the agenda.Green energy utilization includes two aspects,one is the exploitation and promotion of various green energy technologies,and the other is the digitalization of energy management.Under this trend,stochastic and fluctuating energy sources such as wind power and photovoltaic power replace deterministic controllable power sources such as thermal power,bringing challenges to power grid regulation and dispatching,as well as flexible operation.The large-scale integration of renewable energy and increasingly high proportion of power electronic equipment tend to bring about fundamental changes in the operation characteristics,safety control,and production mode of the power system.

Applications of Lithium-Ion Batteries in Grid-Scale Energy Storage Systems

In the electrical energy transformation process,the grid-level energy storage system plays an essential role in balancing power generation and utilization.Batteries have considerable potential for application to grid-level energy storage systems because of their rapid response,modularization,and flexible installation.Among several battery technologies,lithium-ion batteries(LIBs)exhibit high energy efficiency,long cycle life,and relatively high energy density.In this perspective,the properties of LIBs,including their operation mechanism,battery design and construction,and advantages and disadvantages,have been analyzed in detail.Moreover,the performance of LIBs applied to grid-level energy storage systems is analyzed in terms of the following grid services:(1)frequency regulation;(2)peak shifting;(3)integration with renewable energy sources;and(4)power management.In addition,the challenges encountered in the application of LIBs are discussed and possible research directions aimed at overcoming these challenges are proposed to provide insight into the development of grid-level energy storage systems.

Power management in co-phase traction power supply system with super capacitor energy storage for electrified railways

Increasing railway traffic and energy utilization issues prompt electrified railway systems to be more economical,efficient and sustainable.As regenerative braking energy in railway systems has huge potential for optimized utilization,a lot of research has been focusing on how to use the energy efficiently and gain sustainable benefits.The energy storage system is an alternative because it not only deals with regenerative braking energy but also smooths drastic fluctuation of load power profile and optimizes energy management.In this work,we propose a co-phase traction power supply system with super capacitor(CSS_SC)for the purpose of realizing the function of energy management and power quality management in electrified railways.Besides,the coordinated control strategy is presented to match four working modes,including traction,regenerative braking,peak shaving and valley filling.A corresponding simulation model is built in MATLAB/Simulink to verify the feasibility of the proposed system under dynamic working conditions.The results demonstrate that CSS_SC is flexible to deal with four different working conditions and can realize energy saving within the allowable voltage unbalance of 0.008%in simulation in contrast to 1.3%of the standard limit.With such a control strategy,the performance of super capacitor is controlled to comply with efficiency and safety constraints.Finally,a case study demonstrates the improvement in power fluctuation with the valley-to-peak ratio reduced by 20.3%and the daily load factor increased by 17.9%.

An Efficient Summer Operation Scheme for a Thermal Power Plant Air Cooling System based on Electric Peak Shaving

We proposed a novel efficient operation scheme for a thermal power plant’s air-cooling system based on peak shaving, in order to cope with high ambient temperature in summer. We introduced an absorptiongeneration equipment with water/lithium working pairs into the air cooled condenser(ACC) to reconstruct the traditional thermal power plant, and established a dynamic thermodynamic model adopting Ebsilon code. We studied the thermodynamic performance variation of the reconstructed thermal power plant throughout a 24-hour cycle and found that the fluctuation ratio of the turbine back pressure decreased to 6% from 78%, which is beneficial for the stable and safe operation of the electric power system. The thermal performance improvement benefited from the exploitation of the heat transfer potential of ACC, which realized via cold duty schedule throughout the day, under different ambient temperature conditions. In this system, the generated power was higher at relatively high ambient temperature than that at relatively low ambient temperature, which solved the electricity demand-supply imbalance problem under high ambient temperature. Finally, the same optimization effects for power thermal plants with an indirect air-cooling system were obtained using the same operation scheme.

可再生能源电制氢合成氨系统的并/离网运行方式与经济性分析

可再生能源电制氢合成氨(renewablepowerto ammonia,Re Pt A)是风力发电、光伏发电等可再生能源的大规模消纳方式之一,也是化工行业实现低碳清洁发展的重要技术路线之一。利用风电光伏电解水制氢合成氨系统模型,分析电网调峰型系统、电网友好型系统、工艺离网型系统的绿氨成本,并对电化学储能设备规模、储氢设备规模、电解水制氢设备规模、电解水制氢设备效率等影响因素进行敏感性分析。基于3种绿氨系统的设备配置方案和运行方式评估不同类型系统所需的电网调峰电量,提出3种系统所适合的应用场景。研究结论是近期应该发展电网友好型RePtA系统,远期应该发展工艺离网RePtA系统。

太阳能辅助热电联产机组供热、发电及调峰性能分析

针对新能源存在不稳定性导致电网调峰问题日益严重的现状,结合较为成熟的光煤互补发电技术及多热源联合供热调峰系统,设计光煤混合供热发电系统,使热电联产机组具有一定的调峰能力。以某300 MW热电联产机组为研究对象,利用Ebsilon Professional软件搭建发电、供热可灵活调节的太阳能辅助热电联产系统,基于供热机组实际双机运行工况,在保证供热负荷前提下,分析太阳能辅助双机热电联产机组耦合方式,比较耦合前后双机调峰性能。结果表明:凝汽器出口与太阳能集热系统换热器间的管道上设置动态节流阀,改变太阳能集热系统辅助供热机组的运行模式,能够实现发电、供热、调峰一体系统的灵活运行;其中,以太阳能集热系统仅用于补充供暖的运行方式调峰能力最强,太阳能辅助单机供热前后调峰容量比值为0.76,太阳能辅助双机供热前后调峰容量比值为0.55,太阳能辅助承担最大供热负荷的1号机组在调峰容量及调峰补偿上效果最佳。

计及深度调峰的风-光-水-火-抽蓄多能源联网系统优化调度研究

多种能源联网运行逐步成为未来电力系统发展的方向,多能源联网系统的优化调度是应对规模化新能源并网消纳的重要手段。文中建立了计及火电机组深度调峰成本的风-光-水-火-抽蓄联网系统成本模型和考虑调峰主动性的风-光-水-火-抽蓄联网系统日前优化调度模型。针对多能源耦合系统结构复杂的情况,提出了分层优化调度的模型求解策略。上层模型以净负荷波动最小为优化目标,得到等效负荷曲线;下层模型根据上层模型的调度结果,以调峰运行的经济性最优和新能源弃电率最低为目标函数,计及调峰主动性,求解考虑火电机组深度调峰煤耗特性的含新能源系统的经济调度问题。仿真算例表明所建模型实现了多能源联网系统的互补运行,提升了火电机组的深度调峰能力,降低新能源弃电率和系统运行成本。

基于SOEC-OEC双工艺耦合的火电机组全容量长寿命调峰技术研究

现有火电灵活性改造方案难以消除频繁快速变负荷所带来的热力系统寿命折损与机组安全运行风险,为保障火电机组参与电网调峰的安全性、经济性与健康性,提出并构建了基于固体氧化物电解槽(SOEC)制氢技术与燃烧器局部富氧燃烧(OEC)技术相耦合的火电机组全容量长寿命调峰技术方案。以某超超临界1 000 MW二次再热机组为计算示例,对SOEC-OEC系统参与70%~100%的电网深度调峰进行了能效计算,并与常规碱性水电解制氢(ALK)系统进行了比较。计算结果表明,SOEC-OEC技术方案中抽汽电解制氢系统的能效高达49.86%,相比ALK系统提高约26.40%;富氧助燃系统最大可减少锅炉排烟量达23.7%,降低机组供电煤耗2.83 g/(kW·h),减少碳排放约2.82 t/h。此外,SOEC-OEC系统还可为机组带来超额的调峰补贴收益、氢气售卖收益、富氧节煤降碳收益以及设备延寿延保收益等,充分保障了火电调峰过程的经济高效、安全环保。

考虑高比例新能源消纳和火电机组调峰补偿的电力现货市场交易机制设计

针对新能源参与市场竞争和保障性消纳的矛盾,设计高比例新能源电力系统现货市场交易机制。首先,考虑到新能源的市场性消纳,对电力现货市场现有出清机制进行改进,在新能源和火电机组共同参与市场竞价的交易环境下建立出现弃风弃光时触发的发电替代模型,调动火电机组调峰能力,由新能源替代火电进行发电;其次,提出激励相容的结算机制,由新增消纳空间的新能源给予火电机组调峰补偿;最后,对不同调度场景进行仿真计算,结果表明所提机制能够在电力现货市场中实现调峰资源的供需匹配,促进新能源市场化消纳的同时补偿火电机组调峰费用,保证市场主体竞争公平、收益合理。

火电耦合压缩空气储能技术研究进展及展望

火电耦合压缩空气储能技术作为一种提升传统火电机组灵活性和经济性的有效手段,近年来受到了广泛关注。该文从分析火电耦合压缩空气储能技术在提升电网调峰能力、促进可再生能源整合等方面的重要意义出发。首先,介绍典型耦合系统的结构组成与工作原理;然后,探讨耦合系统中关键设备的技术现状和面临的挑战;之后,梳理火-储耦合系统的集成方案设计、调峰运行优化以及经济性评估的研究现状;最后,针对当前技术难点,展望未来火电耦合压缩空气储能技术的研究方向与重点。该文旨在为今后相关领域研究提供参考与借鉴,推动其持续发展和创新。

计及需求响应的光热电站参与深度调峰的分层优化调度策略

从源、荷两侧挖掘系统调峰潜力,建立计及需求响应的光热电站参与深度调峰的分层优化调度模型。上层从负荷侧出发,提出一种基于负荷分类的价格需求响应模型,可有效缓解系统调峰压力;中层从电源侧出发,利用光热电站灵活的调节特性在深度调峰时段协调火电机组参与辅助调峰,构建以运行总成本最小为目标函数的日前调度模型;下层提出一种基于模型预测控制的日内动态调整模型,在滚动优化的同时,通过状态反馈环节实时调整光热电站储热装置充放热修正日前调度计划。仿真结果表明,所提调度策略在降低系统调峰成本的同时能有效抑制风光以及负荷的短时功率波动,在保证系统安全稳定运行的前提下提升风光消纳率。

盘管式冰蓄冷空调技术蓄冰过程理论与实验研究

冰蓄冷空调系统对电网调峰及改善用冷经济性有重要作用。该文通过对盘管式冰蓄冷系统的蓄冰过程研究发现,蓄冰过程包含两个明显阶段:第1阶段,10.0到4.0℃过程中,水的密度随温度降低而增大,4.0℃冷水迅速聚集到蓄冷单元底部,并逐渐充满整个水域;第2阶段,4.0到0℃过程中,水的密度随着温度降低而减小。前期,换热管下表面最先出现冰层;后期,随着上方聚集的低温水增多,换热管上表面开始产生冰层。该实验中,当蓄冰过程进行到100 min时,换热管上下表面冰层厚度均达到8.56 mm。之后,上表面冰层厚度逐渐超过下表面。该研究揭示冰蓄冷单元内部自然对流及4.0℃时水的密度逆转对结冰过程的影响规律,对盘管式冰蓄冷系统的优化设计及运行控制有一定指导意义。

面向电网调峰的盘管式冰蓄冷空调技术研究

储能是助力实现碳达峰碳中和战略目标的关键技术。当前电力供需关系的矛盾随着可再生能源高比例接入和电力需求快速增长日益尖锐,该问题在夏季用电高峰期间尤为突出。冰蓄冷空调系统在夜间利用谷电制冰储存冷量,在白天用电高峰时融冰供冷,有助于电网调峰和改善用能经济性。该文总结分析盘管式冰蓄冷空调关键技术的研究现状和发展方向。系统控制层面:对比分析冰蓄冷空调系统的各种优化控制策略;蓄冰融冰方式层面:详细阐述内融冰、外融冰和内外融冰结合3种方式特点,并对能量模型进行归纳;结构层面:分析典型强化传热方式对传热性能的影响关系。最后,归纳不同材质盘管的研究结果与应用前景。

风-火-储耦合系统储能容量配置优化对比

为提升风电富集区域风电消纳水平及燃煤机组的灵活性,提出了基于热电共蓄式压缩空气储能的风-火-储耦合系统及系统调度策略,建立了系统的容量配置优化框架,并对7种布局方案进行了多目标优化。优化结果表明:电锅炉将弃风电量转化为热量时,燃煤机组的运行点向电力负荷下限更低的区域移动,风电上网空间增大,燃煤机组出力水平降低;加入热电共蓄式压缩空气储能子系统,使得燃煤机组电功率水平降低;换热器废热的回收进一步降低了燃煤机组产热水平;通过调整燃煤机组热出力,抽汽蓄热子系统能够实现抽汽热的时空平移,促使燃煤机组运行点向电力负荷下限更低的区域移动,可间接促进风电的消纳。综合来看,3种子系统相组合的最佳耦合方案可实现燃煤机组的热电解耦,从而提升了其深度调峰能力,在更大程度消纳风电能力的同时提升了系统的效率和环保性。

考虑储热装置多级特斯拉阀性能优化的热电机组调峰能力分析

随着风电并网容量与日俱增,热电机组调峰难度不断增加,由此导致弃风问题日趋严重。为有效缓解上述问题,提出将传统储热装置用多级特斯拉阀进行性能优化,扩大热电机组电-热特性区间,通过提升调峰能力来提高风电的消纳水平。首先,对特斯拉阀端口特性进行了分析,创新性地提出了一种基于多级特斯拉阀的新型储热装置,并在其传热与流动特性分析基础上构建了储热装置的模型;其次,对新型储热装置两种运行策略进行建模分析,证明了热电机组装配新型储热装置后能够提升调峰能力;最后,对热电机组的电-热特性区间和调峰能力的变化进行对比,结果表明,热电厂中配置含多级特斯拉阀的新型储热装置,可有效扩大热电机组电-热特性区间,提高调峰能力,同时缓解弃风问题。

火-储耦合系统深度调峰综合经济性分析

火电机组耦合储热技术,可提高机组的热电解耦能力,减少深度调峰对系统安全性和经济性的影响。本工作提出了火电机组与填充床储热的耦合系统,在考虑了机组变工况、填充床储/释热过程动态时间序列基础上,通过EBSILON建立了耦合系统变工况仿真模型;分析深度调峰对耦合系统热力性和碳排放量的影响,通过汽水分离器筒体应力变化分析深调对锅炉寿命损耗的影响,通过转子寿命损耗率曲线分析深调对汽轮机寿命的影响,最终建立耦合系统调度运行经济性模型,开展综合经济性分析。结果表明:火-储耦合系统比自身变工况减小碳排放量7418 t/a(仅配置风电)~9216 t/a(仅配置光伏);深度调峰对锅炉寿命损耗的影响大于汽轮机,火-储耦合系统可提高系统运行寿命,深度调峰318次/年,相比于机组自身变工况(30%~20%额定负荷)可提高13.3%~15.3%;火-储耦合系统深度调峰收益高于火电机组自身变工况,当填充床释热量用于发电或供热时,耦合系统比自身变工况收益分别增加40万元/年、72万元/年。

330 MW循环流化床锅炉深度调峰技术

为推进“双碳”政策的实施,消纳波动性较强的新能源并网发电,当前对火电机组的深度调峰要求越来越高。循环流化床(circulating fluidized bed,CFB)锅炉机组在深度调峰低负荷运行工况有着先天优势,但实现20%以下的超低负荷运行依然面临众多的困难,如炉内流化的稳定性、氮氧化物的排放及炉内局部超温带来的安全性等问题。以某330 MW CFB锅炉的深度调峰技术应用为例,介绍了输煤筛分破碎系统、风帽节流圈、下二次风管等机组部件的改造,并配合烟气再循环等技术应用,成功实现了18%的超低负荷深度调峰运行,同时也很好地控制了NOx的排放。最后总结了CFB机组超低负荷深度调峰技术的关键点和难点,对深度调峰运行带来的潜在问题进行了分析,并提出了相应的解决措施。研究结果具有重要的工程借鉴作用。