Network security protection technology for a cloud energy storage network controller

As part of the ongoing information revolution, smart power grid technology has become a key focus area for research into power systems. Intelligent electrical appliances are now an important component of power systems, providing a smart power grid with increased control, stability, and safety. Based on the secure communication requirements of cloud energy storage systems, this paper presents the design and development of a node controller for a cloud energy storage network. The function division and system deployment processes were carried out to ensure the security of the communication network used for the cloud energy storage system. Safety protection measures were proposed according to the demands of the communication network, allowing the system to run safely and stably. Finally, the effectiveness of the system was verified through a client-side distributed energy storage demonstration project in Suzhou, China. The system was observed to operate safely and stably, demonstrating good peak-clipping and valley filling effects, and improving the system load characteristics.     

Evaluation of distributed building thermal energy storage in conjunction with wind and solar electric power generation

Energy storage is often seen as necessary for the electric utility systems with large amounts of solar or wind power generation to compensate for the inability to schedule these facilities to match power demand. This study looks at the potential to use building thermal energy storage as a load shifting technology rather than traditional electric energy storage. Analyses are conducted using hourly electric load, temperature, wind speed, and solar radiation data for a 5-state central U.S. region in conjunction with simple computer simulations and economic models to evaluate the economic benefit of distributed building thermal energy storage (TES). The value of the TES is investigated as wind and solar power generation penetration increases. In addition, building side and smart grid enabled utility side storage management strategies are explored and compared. For a relative point of comparison, batteries are simulated and compared to TES. It is found that cooling TES value remains approximately constant as wind penetration increases, but generally decreases with increasing solar penetration. It is also clearly shown that the storage management strategy is vitally important to the economic value of TES; utility side operating methods perform with at least 75% greater value as compared to building side management strategies. In addition, TES compares fairly well against batteries, obtaining nearly 90% of the battery value in the base case; this result is significant considering TES can only impact building thermal loads, whereas batteries can impact any electrical load. Surprisingly, the value of energy storage does not increase substantially with increased wind and solar penetration and in some cases it decreases. This result is true for both TES and batteries and suggests that the tie between load shifting energy storage and renewable electric power generation may not be nearly as strong as typically thought.     

Analysis of access mode and control strategy of distributed energy storage system on user side

分布式储能系统在电力用户侧中的应用日益广泛,且应用场景多样化,对于电网来说是潜在的优良资源。然而其容量小、数量多、分布不均衡、单机接入成本高、系统操作及管理困难,给电网的规划运营带来了日益严峻的挑战和技术难题。本文就用户侧中的分布式储能典型应用模式及接入方式进行介绍,阐述各应用场景下分布式储能的应用模式和方案,并分析了典型应用场景下的分布式储能运行效果。通过对分布式储能系统技术形态和载体的分析,可为进一步研究分布式储能汇聚协调控制技术提供理论指导。     

Two-level energy management strategy for PV-Fuel cell-battery-based DC microgrid

With the fast development of DC Microgrid (MG) technology, its operating economy and reliability are getting more and more concern. The traditional distributed control method is aimed at power balance and system stability, and is difficult to meet the requirement of energy management system for multi-source hybrid DC MG. This paper provides a two-level energy management strategy for PV-fuel cell-battery-based DC MG, which is divided into device control level and system control level. At the device control level, the distributed control methods based on MPPT-droop dual-mode control and droop control are proposed to enhance system reliability; at the system control level, the equivalent consumption minimization strategy (ECMS) is used to distribute system net power between battery pack and fuel cell system. A lab-scale DC microgrid platform is developed to verify the proposed energy management strategy in this paper. Moreover, the analysis and compare of the results show that the proposed two-level energy management strategy can achieve lower equivalent hydrogen consumption than classical PI control and state machine control method.     

考虑储能容量的电网电能质量治理策略

为提高储能参与电网电能质量治理的能力,延长储能系统寿命,文章提出了一种考虑储能容量的电能质量治理策略.首先,介绍了储能变流器(Power Conversion System,PCS)的结构,并给出了参考电流生成方法;随后,根据储能系统当前容量,选择补偿控制方法,并重点针对储能容量不足情况,提出了基于比例矢量比例积分(P...     

微网中储能系统的控制与分析

在微网系统中,大功率电力负荷的投切会导致电网电压幅值和频率产生波动。将储能装置应用于微网系统中,可以通过逆变控制单元,实时监控电网电压波动,即时调节配电网输送的有功、无功功率大小,从而达到平抑电网电压波动的效果。采用了电压频率环控制和有功、无功补偿控制相结合的控制算法,可以即时检测电网电压波动并进行快速补偿,具有较强的有功、无功调节能力。通过构建微网模拟环境,对比试验了不加储能装置和接入储能装置后微电网投入不同电力负荷时的电压波动情况,验证了控制策略的有效性和正确性。     

Integrated battery controller for distributed energy system

In this article, an improved integrated battery energy storage system (BESS) controller for distributed energy system is presented. The BESS is integrated in parallel with the full wave bridge converter into the distributed energy system network. In a normal operating mode, the BESS serves as a power conditioner as well as an active power filter in a distributed power system network. This work presents BESS controller which is designed for regulating the state of charge of the batteries and also to manage the active power in a distributed power system network. The off peak load energy is used to recover the batteries’ state of charge through the BESS controller. In this BESS controller, the constant current-constant voltage (CC-CV) mode is used and it helps to keep the batteries’ state of charge conditions for improving the reliability of the distributed power system system. This control strategy is incorporated into the main converter. The controller helps in managing the phase, amplitude and waveform of the current and voltage on the distributed power system network. The controller ensures the power quality and also assists in improving the power factor with respect to the utility for the intermittent distributed generation as well as the load. In this article, the test results of a prototype system are presented, which validates the proposed controller strategy of BESS in a distributed power system network.     

基于负荷预测的储能功率分配优化策略

针对目前电力系统调峰、调频储能电站容量有限的情况,文章提出了一种基于负荷预测的储能电站调峰、调频功率分配策略。首先建立了基于遗传算法(Genetic Algorithm,GA)优化BP神经网络的负荷预测模型,对电力系统中的负荷进行精准的预测,为储能电站参与调峰、调频提供计划调度参考;在此基础上,计及储能电站参与调峰、调频辅助服务的收益以及成本,建立储能电站参与调峰、调频功率分配经济模型,并利用粒子群算法对其进行优化求解,确定储能电站最优分配结果;最后,基于MTALAB仿真平台,验证了所提功率分配策略的有效性。     

Distributed photovoltaic generation and energy storage systems: A review

Currently, in the field of operation and planning of electrical power systems, a new challenge is growing which includes with the increase in the level of distributed generation from new energy sources, especially renewable sources. The question of load redistribution for better energetic usage is of vital importance since these new renewable energy sources are often intermittent. Therefore, new systems must be proposed which ally energy storage with renewable energy generators for reestablishment of grid reliability. This work presents a review of energy storage and redistribution associated with photovoltaic energy, proposing a distributed micro-generation complex connected to the electrical power grid using energy storage systems, with an emphasis placed on the use of NaS batteries. These systems aim to improve the load factor, considering supply side management, and the offer of backup energy, in the case of demand side management.     

Compact energy storage: Opportunities and challenges of graphene for supercapacitors

碳纳米储能材料发展迅速,质量容量性能不断刷新。但通常碳纳米材料的密度较低,导致其体积比容量有限,在很多时候很难将材料水平上的优异性能反映到最终的器件上。发展高体积能量密度储能材料,在器件水平上实现致密储能,对推动储能材料和器件的实用化至关重要。作为其它sp2碳质材料的基本结构单元和一种柔性二维材料,石墨烯通过组装可以实现纳米结构致密化,在致密储能方面具有先天优势。本文以石墨烯在超级电容器中的应用为主,分别从材料、电极、器件3个层次讨论了实用化储能器件的设计原则,梳理了高体积能量密度碳基储能材料的研究进展,重点介绍了高体积容量碳电极材料的致密化设计理念,强调了从器件角度考虑储能材料设计的重要性,并对致密储能面临的机遇和挑战作了分析。     

储能系统协同常规机组调峰控制策略研究

大规模风电并网会引起电力系统调峰能力不足,造成火电机组频繁启停或弃风。文章利用电池储能充放电灵活、可补充常规机组调峰能力不足的特性,提出了AGC机组、NON-AGC机组与储能系统间的协调控制策略。该策略引入了改进调度时间级,实现储能与常规机组时间协调配合;以AGC机组与NON-AGC机组的协调机制为基础,建立了AGC机组向NON-AGC机组与电池储能的转移功率模型。根据前一时刻机组的输出功率,计算出机组的调节余量实现电池储能参与系统调峰。实际系统算例分析结果表明,所提控制策略的可行性和有效性。     

An energy storage system for smart coal mine emergency power supply

为满足煤炭行业和煤矿企业对于供电可靠性日益增长的需求,同时探索兆瓦级储能系统在工业用户侧的实用化解决方案,本项目在内蒙古乌海平沟煤矿设计建造了基于铅酸电池和磷酸铁锂电池储能技术的矿用兆瓦级智能应急电源。系统主要功能为：在电网正常供电时,替代传统的油浸电容器进行无功补偿;在电网出现供电故障时,为煤矿的特别重要负荷提供至少30 min的连续可靠供电。除此外,系统还可根据用户需求执行包括削峰填谷、分布式新能源发电波动平抑在内的多种功能。为保证应急电源系统的安全性、可靠性和使用寿命,本工作在进行设计时着重考虑了蓄电池的选型、容量配比、成组设计以及储能变流系统（PCS）的电路拓扑设计和电池维护高级智能控制策略,旨在探索和实用。     

Dynamic modeling of hybrid energy storage systems coupled to photovoltaic generation in residential applications

A model of a photovoltaic (PV) powered residence in stand-alone configuration was developed and evaluated. The model assesses the sizing, capital costs, control strategies, and efficiencies of reversible fuel cells (RFC), batteries, and ultra-capacitors (UC) both individually, and in combination, as hybrid energy storage devices. The choice of control strategy for a hybrid energy storage system is found to have a significant impact on system efficiency, hydrogen production and component utilization. A hybrid energy storage system comprised of batteries and RFC has the advantage of reduced cost (compared to using a RFC as the sole energy storage device), high system efficiency and hydrogen energy production capacity. A control strategy that preferentially used the RFC before the battery in meeting load demand allows both grid independent operation and better RFC utilization compared to a system that preferentially used the battery before the RFC. Ultra-capacitors coupled with a RFC in a hybrid energy storage system contain insufficient energy density to meet dynamic power demands typical of residential applications.     

Research on optimal confguration of hybrid energy storage capacity for wind-solar generation system

储能系统可以有效解决微电网中分布式可再生能源特别是风光互补发电的间歇性、波动性以及“源”与“荷”错位的问题。不同储能技术在响应时间、容量规模、技术成熟度及成本等方面各有特点,两种或多种储能技术耦合将可以更有效地满足用电系统的技术性和经济性的要求。针对电力用户对分布式可再生能源的利用情况,本文提出一种由压缩空气储能、锂电池和超级电容器组成的混合储能系统,建立了三种储能的数学模型,针对其不同的特性,提出了基于二次移动平均滤波的储能系统功率分配方法和基于连续性运行的容量优化配置方法。基于某个实际的用户负荷进行了案例分析,得到了混合储能系统的功率和容量配置结果,并分析了其运行特性。研究表明,在分布式可再生能源微电网中,多种储能技术耦合既能充分发挥每种储能的优势,又可以通过相互配合弥补各自的劣势,这对于可再生能源的充分利用和满足用电负荷的严苛需求具有重要的作用和意义,在分布式能源利用领域具有较好的工程应用前景。     

Solar multi-mode heating system based on latent heat thermal energy storage and its application

为克服太阳能间断性和不稳定性的缺点进而实现太阳能集热与采暖的能量供需调节和全天候连续供热,提出了基于相变储热的太阳能多模式采暖方法（太阳能集热直接采暖、太阳能集热采暖+相变储热、太阳能相变储热采暖）,并在西藏林芝市某建筑搭建了太阳能与相变储热相结合的采暖系统,该系统可根据太阳能集热温度和外界供热需求实现太阳能多模式采暖的自动控制和自动运行。实验研究表明：在西藏地区采用真空管太阳能集热器可以和中低温相变储热器很好地结合,白天储热器在储热过程中平均储热功率为10.63 kW,储热量达到92.67 kW·h,相变平台明显;晚上储热器在放热过程中供热量达85.23 kW·h,放热功率和放热温度平稳,储放热效率达92%,其储热密度是传统水箱的3.6倍,可连续供热时间长达10 h,从而实现了基于相变储热的太阳能全天候连续供热,相关研究结果对我国西藏地区实施太阳能采暖具有一定的指导作用。     

The study of control strategy for urban mass transit based on flywheel energy storage system

针对城市轨道交通列车运行密度高,起制动功率大的特点,采用飞轮型再生制动能量回收装置可有效降低直流牵引网压波动,降低牵引能耗。由于该装置采用基于直流牵引网母线电压高低进行充放电的控制策略,在实际运行工况中可能存在无法准确识别再生能或储能设备SOC值无法自动调整导致无法再响应牵引网压波动的情况,本文提出空载网压识别和SOC自适应控制策略进行解决,通过轨道交通试验平台的试验验证,得出该控制策略的有效性。     

Operation strategy of distributed energy storage system with multi-battery under output smoothing scenario

随着光伏发电在电网中渗透率的不断增加,光伏发电功率的不确定性和间歇性引起的光伏并网和弃电问题已引起关注。而采用"光伏+储能"的模式,却能有效缓解这一问题。在考虑储能电池容量衰退和光伏弃电率下,通过对不同光伏子阵配备的不同类型储能电池系统的运行进行仿真模拟,以消除光伏发电随机波动特性对电网的冲击为目的,研究平滑输出场景下分布式储能系统的电池的操作策略,优化储能系统中各储能电池子阵的运行。最后,采用共和地区20 MW （峰值）储能实证基地项目多电池储能系统实际案例对本模拟方法进行了验证。     

Primary energy savings through thermal storage in district heating networks

District heating is an efficient way to provide heat to residential, tertiary and industrial users. Heat is often produced by CHP (combined heat and power) plants, usually designed to provide the base thermal load (40-50% of the maximum load) while the rest is provided by boilers. The use of storage tanks would permit to increase the annual operating hours of CHP: heat can be produced when the request is low (for instance during the night), stored and then used when the request is high. The use of boilers results partially reduced and the thermal load diagram is flattered. Depending on the type of CHP plant this may also affect the electricity generation. All these considerations are crucial in the free electricity market.In this paper, a multi-scale model of storage tanks is proposed. This model is particularly suitable to analyze the operation of storage systems during the heating season and to predict their effects on the primary energy consumption and cash flows. The analysis is conducted considering the Turin district heating system as case study. Results show that primary energy consumption can be reduced up to 12%, while total costs can be reduced up to about 5%.     

Power smoothing control for wind farms using flywheel based energy storage

在风电场增设飞轮储能装置可以有效地平抑风电场的功率波动,提高电网的风电接纳能力。本文采用在风电场出口母线处接入飞轮储能装置,通过分析风电系统和飞轮储能装置的特性,提出了一种基于瞬时功率理论的有功功率平滑控制策略。在传统低通滤波器的基础上,增加高通滤波器,对网侧有功功率的快速扰动成分进行处理,最终通过低通、高通滤波器来获得飞轮装置的补偿功率,达到对网侧有功功率波动进行抑制的目的。最后利用Matlab/Simulink进行仿真验证,仿真结果表明,文中的控制策略可以较好地实现电网侧有功功率的平滑控制,减小有功功率波动。     

Application and control of super capacitor in high-speed railway regenerative braking energy storage

针对高速列车在制动过程中产生的再生制动能量得不到有效利用的问题,提出一种基于超级电容（supercapacitor,SC）的高速铁路再生制动能量存储方案。该方案以铁路功率调节器（railway power conditioner,RPC）作为接口电路,将储能装置与牵引供电系统连接在一起,采用超级电容作为储能介质,通过双向DC/DC变流器与铁路功率调节器直流侧相连,从而实现能量存储与补偿负序电流的功能。在研究储能方案拓扑结构的基础上,分析了负序电流的补偿原理,并根据补偿原理研究了储能方案的控制策略,对RPC两变流器采用滞环控制的方法,对储能装置中的双向DC/DC变流器采用电流闭环的控制方法。仿真结果表明,所提出的存储方案能够有效回收利用高速列车产生的再生制动能,并对负序电流进行补偿,改善电网侧电能质量。