Investigating Load Regulation Characteristics of a Wind-PV-Coal Storage Multi-Power Generation System

There is a growing need to explore the potential of coal-fired power plants(CFPPs)to enhance the utilization rate of wind power(wind)and photovoltaic power(PV)in the green energy field.This study developed a load regulation model for a multi-power generation system comprising wind,PV,and coal energy storage using realworld data.The power supply process was divided into eight fundamental load regulation scenarios,elucidating the influence of each scenario on load regulation.Within the framework of the multi-power generation system with the wind(50 MW)and PV(50 MW)alongside a CFPP(330 MW),a lithium-iron phosphate energy storage system(LIPBESS)was integrated to improve the system’s load regulation flexibility.The energy storage operation strategy was formulated based on the charging and discharging priority of the LIPBESS for each basic scenario and the charging and discharging load calculation method of LIPBESS auxiliary regulation.Through optimization using the particle swarm algorithm,the optimal capacity of LIPBESS was determined to be within the 5.24-4.88 MWh range.From an economic perspective,the LIPBESS operating with CFPP as the regulating power source was 49.1% lower in capacity compared to the renewable energy-based storage mode.

Optimal Scheduling Method of Cogeneration System with Heat Storage Device Based on Memetic Algorithm

Electric-heat coupling characteristics of a cogeneration system and the operating mode of fixing electricity with heat are the main reasons for wind abandonment during the heating season in the Three North area.To improve the wind-power absorption capacity and operating economy of the system,the structure of the system is improved by adding a heat storage device and an electric boiler.First,aiming at the minimum operating cost of the system,the optimal scheduling model of the cogeneration system,including a heat storage device and electric boiler,is constructed.Second,according to the characteristics of the problem,a cultural gene algorithm program is compiled to simulate the calculation example.Finally,through the system improvement,the comparison between the conditions before and after and the simulation solutions of similar algorithms prove the effectiveness of the proposed scheme.The simulation results show that adding the heat storage device and electric boiler to the scheduling optimization process not only improves the wind power consumption capacity of the cogeneration system but also reduces the operating cost of the system by significantly reducing the coal consumption of the unit and improving the economy of the system operation.The cultural gene algorithm framework has both the global evolution process of the population and the local search for the characteristics of the problem,which has a better optimization effect on the solution.

Three-Level Optimal Scheduling and Power Allocation Strategy for Power System ContainingWind-Storage Combined Unit

To mitigate the impact of wind power volatility on power system scheduling,this paper adopts the wind-storage combined unit to improve the dispatchability of wind energy.And a three-level optimal scheduling and power allocation strategy is proposed for the system containing the wind-storage combined unit.The strategy takes smoothing power output as themain objectives.The first level is the wind-storage joint scheduling,and the second and third levels carry out the unit combination optimization of thermal power and the power allocation of wind power cluster(WPC),respectively,according to the scheduling power of WPC and ESS obtained from the first level.This can ensure the stability,economy and environmental friendliness of the whole power system.Based on the roles of peak shaving-valley filling and fluctuation smoothing of the energy storage system(ESS),this paper decides the charging and discharging intervals of ESS,so that the energy storage and wind power output can be further coordinated.Considering the prediction error and the output uncertainty of wind power,the planned scheduling output of wind farms(WFs)is first optimized on a long timescale,and then the rolling correction optimization of the scheduling output of WFs is carried out on a short timescale.Finally,the effectiveness of the proposed optimal scheduling and power allocation strategy is verified through case analysis.

Application of Power Electronics Converters in Renewable Energy

Against the backdrop of global energy shortages and increasingly severe environmental pollution,renewable energy is gradually becoming a significant direction for future energy development.Power electronics converters,as the core technology for energy conversion and control,play a crucial role in enhancing the efficiency and stability of renewable energy systems.This paper explores the basic principles and functions of power electronics converters and their specific applications in photovoltaic power generation,wind power generation,and energy storage systems.Additionally,it analyzes the current innovations in high-efficiency energy conversion,multilevel conversion technology,and the application of new materials and devices.By studying these technologies,the aim is to promote the widespread application of power electronics converters in renewable energy systems and provide theoretical and technical support for achieving sustainable energy development.

Operation Strategies for Coordinating Battery Energy Storage with Wind Power Generation and Their Effects on System Reliability

The variability of wind power generation requires the allocation of a flexible energy reserve which is capable of compensating for possible imbalances between the load and generation. To reduce the variability of wind power generation and loss of load in generation deficit, we propose operation strategies for coordinating battery energy storage with wind power generation. The effects of the operation strategies on system reliability are evaluated by the developed computation model that represents the main aspects and operation limitations of the batteries. The performance evaluation of the power system is based on the composite reliability indices of loss of load probability(LOLP) and expected energy not supplied(EENS), which is calculated through sequential Monte Carlo simulation. Tests are performed by the developed model with a tutorial system consisting of five busbars and the IEEE RTS system. The results show that the use of large-scale batteries is an alternative to physically guarantee the wind power plants and to act as an operation reserve to reduce the risk of loss of load.

Reliability evaluation of tidal and wind power generation system with battery energy storage

This paper presents a method for reliability evaluation of a hybrid generation system of wind and tidal powers with battery energy storage.Such a system may widely exist in coastal areas and islands in the future.A chronological multiple state probability model of tidal power generation system(TPGS)considering both forced outage rate(FOR)of the TPGS and random nature of tidal current speed is developed.In the evaluation of FORs of TPGS and WPGS(wind power generation system),the delivered power related failure rates of power electronic converters for TPGS and WPGS are considered.A chronological power output model of battery energy storage system(BESS)is derived.A hybrid system of tidal and wind generation powers with a BESS is used to demonstrate the effectiveness of the presented method.In case studies,the effects of various parameters on the system reliability are investigated.

基于AA-CAES电站和综合需求响应的供暖期弃风消纳策略

“双碳”目标背景下,为解决热电联产机组“以热定电”模式导致的大规模弃风问题,本文提出基于先进绝热压缩空气储能电站(advanced adiabatic compressed air energy storage,AA-CAES)和综合需求响应的综合能源系统(integrated energy system,IES)供暖期弃风消纳策略。首先,在“源-储”两侧建立热电联产机组与AA-CAES电站耦合运行模型,分析耦合运行实现热电解耦机理;其次,在“荷”侧引入价格型和替代型需求响应机制来探寻负荷侧优化系统调度潜力;然后,在IES中引入碳捕集系统和阶梯型碳交易机制来约束碳排放,并在碳排放量最少、综合成本最低为目标构建IES运行基础上,引入模糊机会规划约束模型来分析风、光不确定性对系统调度影响;最后,利用西北某地区实际数据进行算例验证。结果表明:热电机组与AA-CAES电站耦合运行相较于未耦合运行可提高风电消纳率84.55%、降低总成本11.42%、减少碳排放20.28%;综合需求响应机制的引入可进一步提高风电消纳率35.00%、降低总成本20.93%、减少碳排放24.43%;风光不确定性的上升会提高与外部电网的交互成本。

计及不确定性的风储联合系统多时间尺度市场参与策略

风电出力的强不确定性严重阻碍了电力市场上报计划的精准执行,由此产生的偏差功率可能使风储联合系统背负高额的偏差惩罚和弃风损失。为了减小投标决策失误导致的经济亏损,建立了一种风储联合系统多时间尺度市场投标模型。借鉴美国现有的市场机制,建立风储联合系统参与能量市场和调频辅助服务市场的收益、成本模型;为了提升风储联合系统投标策略的准确性,基于Copula函数对风电出力不确定性进行量化建模,以此为基础预留部分储能出力能力,从而降低由偏差功率产生的经济性风险;以风储联合系统的预期净收益最大为目标,制定能量市场和调频辅助服务市场的日前投标策略,并在日内阶段根据超短期风电预测数据修正投标决策,提出一种考虑风电出力不确定性的风储联合系统多时间尺度市场参与策略。基于我国某实际风储联合系统进行算例分析,结果表明所提策略能够有效提高风储联合系统的经济收益,避免资源浪费。

基于模型预测控制的风储联合电场参与电网二次调频策略

随着风力发电在电网中渗透率不断增加,需要风储联合电场参与电网调频服务,维持电网的频率稳定.针对中高风速下的风储联合电场,通过分析风力发电机的机械特性和储能系统的运行特性,确定了减载运行方式下风力发电机桨距角的控制方式,提出一种基于模型预测控制的风储联合电场参与电网二次调频的控制策略.建立风电场桨距角控制的预测模型和电化学储能系统的预测模型,优化风力发电机和储能系统的有功功率输出,在调频基础上更好地减少了风能损失.根据上级系统的有功功率指令值和风力发电机实际输出功率之间的差值对桨距角控制进行进一步修正,使得风力发电机在二次调频期间能够更好地追踪到上级系统的功率指令值,迅速响应频率变化值,减小动态频率偏差,完成二次调频任务.仿真结果表明,该控制策略综合考虑了风力发电机可控的二次调频能力和电化学储能系统响应快速、跟踪精确的特性,使风储联合电场能够主动响应系统频率的变化,更好地跟踪上级系统下发的有功功率指令值,参与电网二次调频.

小型风光储联合发电系统的设计

针对新疆维吾尔自治区农牧地区自然资源优势及日益增长的用电需求,设计了一种可移动式小型风光储联合发电系统,用于满足当地居民及牧民对便携式发电设备的需求。对该发电系统的总体设计方案、硬件及软件的设计分别进行了介绍,并通过实验验证了该发电系统能较稳定的跟踪太阳。该发电系统整体上实现了太阳能、风能的独立及互补发电,提高了资源利用率,且其结构简单、价格低廉,作为初级阶段的研究成果可供相关设计参考。

基于改进LADRC的构网型储能调频控制策略研究

为提升高比例风电渗透下电力系统的频率稳定性,同时解决风储联合系统调频过程中参数间相互影响难以兼顾导致系统调频控制性能不佳的问题,提出一种基于改进型线性自抗扰控制策略(linear active disturbance rejection control,LADRC)的构网型(grid-forming,GFM)储能调频控制策略。首先,在传统应用LADRC对角频率进行快速控制的基础上,引入有功差额补偿,加速有功指令响应速度,消除参数互耦。同时,针对构网型储能调频控制策略参数影响规律,分析了角频率和参考功率至输出功率的小信号模型,推导控制环节传递函数,实现对系统调频性能优化。最后在Matlab/Simulink仿真平台上搭建风储联合系统仿真模型,对不同控制策略在不同工况下电网频率和储能出力的变化情况进行对比分析。结果表明,所提控制策略有效提升复杂工况下风储联合系统对电网频率的支撑能力。

考虑风-储频率响应的智能电网频率特征分析

随着新型电力系统的提出,新能源渗透下的智能电网得到巨大发展。以风电、储能为代表的高比例新能源和大量电力电子设备并网,使得传统火电比例降低,在一定程度上带来了许多频率安全问题。为明晰风-储参与调频下电网频率态势,根据传统火电、风电、储能频率响应模型分析了各调频单元调频控制原理;根据调频控制原理对各调频单元进行参数整定,并得到风-储参与调频下电网的参数整定关系;通过稳态频率误差公式得到稳态频率误差与传统火电、风电调频系数的数量关系,利用伯德图分析储能控制比例参数对频率稳定性的影响,并根据根轨迹图分析惯性时间常数对智能电网频率稳定趋势的影响;通过MATLAB/Simulink仿真平台对理论分析进行验证。仿真表明通过时域和频域对频率特性进行分析可有效预测火电、风电、储能参与调频下智能电网频率态势,可为风-储参与调频下电网安全稳定运行与控制提供指导。

Market-oriented Optimal Dispatching Strategy for a Wind Farm with a Multiple Stage Hybrid Energy Storage System

With the increased promotion of integrated energy power systems(IEPS),renewable energy and energy storage systems(ESS)play a more important role.However,the fluctuation and intermittent nature of wind not only results in substantial reliability and stability defects,but it also weakens the competitiveness of wind generation in the electric power market.Meanwhile,the way to further enhance the system reliability effectively improving market profits of wind farms is one of the most important aspects of Wind-ESS joint operational design.In this paper,a market-oriented optimized dispatching strategy for a wind farm with a multiple stage hybrid ESS is proposed.The first stage ESS is designed to improve the profits of wind generation through day-ahead market operations,the real-time marketbased second stage ESS is focused on day-ahead forecasting error elimination and wind power fluctuation smoothing,while the backup stage ESS is associated with them to provide the ancillary service.An interval forecasting method is adopted to help to ensure reliable forecast results of day-ahead wind power,electricity prices and loads.With this hybrid ESS design,supply reliability and market profits are simultaneously achieved for wind farms.

Frequency-constrained Co-planning of Generation and Energy Storage with High-penetration Renewable Energy

Large-scale renewable energy integration decreases the system inertia and restricts frequency regulation. To maintain the frequency stability, allocating adequate frequency-support sources poses a critical challenge to planners. In this context, we propose a frequency-constrained coordination planning model of thermal units, wind farms, and battery energy storage systems (BESSs) to provide satisfactory frequency supports. Firstly, a modified multi-machine system frequency response (MSFR) model that accounts for the dynamic responses from both synchronous generators and grid-connected inverters is constructed with preset power-headroom. Secondly, the rate-of-change-of-frequency (ROCOF) and frequency response power are deduced to construct frequency constraints. A data-driven piecewise linearization (DDPWL) method based on hyperplane fitting and data classification is applied to linearize the highly nonlinear frequency response power. Thirdly, frequency constraints are inserted into our planning model, while the unit commitment based on the coordinated operation of the thermal-hydro-wind-BESS hybrid system is implemented. At last, the proposed model is applied to the IEEE RTS-79 test system. The results demonstrate the effectiveness of our co-planning model to keep the frequency stability.

Energy Storage Modeling of Inverter Air Conditioning for Output Optimizing of Wind Generation in the Electricity Market

In order to achieve the compatibility of the air conditioning(AC)loads with the current dispatch models,this pa-per utilizes demand response(DR)technology as energy storage resources to optimize the aggregator’s behaviors in the real-time market for less economic loss caused by the fluctuations of wind power.The inverter AC,as a typical demand response resource,is constructed as a power type battery model(PTBM)and a capacity type battery model(CTBM)according to the different control methods,which are expressed through a circuit model and mathematical model to describe the energy storage characteristics of ACs.Moreover,the comparisons between the PTBM and CTBM are given analytically by their response speed,power&energy capacity and the cost of control,which will be helpful to guide the associated operators to choose the appropriate models to take part in demand response.Considering that the wind generation fluctuates frequently and greatly,the PTBM is chosen to take part of the demand response for output optimizing of the wind generation.The simulation results demonstrate that PTBMs can work in the way of conventional batteries(CBs)to optimize wind generation in the real-time market.

A general analytical approach to reach maximum grid support by PMSG-based wind turbines under various grid faults

A novel fault ride-through strategy for wind turbines,based on permanent magnet synchronous generator,has been proposed.The proposed strategy analytically formulates the reference current signals,disregarding grid fault type and utilizes the whole system capacity to inject the reactive current required by grid codes and deliver maximum possible active power to support grid frequency and avoid generation loss.All this has been reached by taking the grid-side converter’s phase current limit into account.The strategy is compatible with different countries’grid codes and prevents pulsating active power injection,in an unbalanced grid condition.Model predictive current controller is applied to handling rapid transients.During faults,the energy storage system maintains DC-link voltage,which causes voltage fluctuations to be eliminated,significantly.A fault ride-through strategy was proposed for PMSG-based wind turbines,neglecting fault characteristics,second,reaching maximum possible grid support in faulty grid conditions,while avoiding over-current and third,considerable reduction in energy storage system size and power rating.Inspiring simulations have been carried out through MATLAB/SIMULINK to validate the feasibility and competency of the proposed fault ride-through method and efficiency of the entire control system.

考虑风-储-直参与调频的电力系统频率特征定量分析

以风电、储能、柔性直流输电为代表的高比例可再生能源和大量电力电子设备的并网,使得电网中传统火电的比例下降,这将在一定程度上影响电力系统的频率稳定性。为定量分析风电、储能、柔性直流输电系统参与调频下电力系统的频率特征,首先提出多种调频资源参与调频下的电网频率特征定量分析总体思路,建立风-储-直调频频率响应模型。然后基于频率特性传递函数对电力系统稳态频率偏差、初始频率变化率、最大频率偏差和频率安全裕度进行理论推导;且定量分析了稳态频率偏差变化规律以及惯性时间常数、辅助调频单元控制比例系数对频率稳定性的影响,并计算稳态频率偏差与功率扰动的关系。最后,基于仿真软件验证了所提分析方法的可行性和有效性。仿真表明所提方法可有效定量分析电力系统频率特征,可为双高电力系统下电网频率安全稳定运行与控制提供指导依据。

依托重力储能的高寒地区风-储联合发电系统容量优化

如何合理规划风电场和重力储能的容量是保证高寒地区风-储联合发电系统可靠性和经济性的前提。提出一种以系统总成本最小为目标函数的并网型风-储联合发电系统容量优化模型,同时兼顾垂直式和斜坡式2种重力储能形式。以风-荷匹配率、供电可靠性、风-储联合发电系统占总率等评价指标作为约束条件,采用加入教育策略的遗传算法进行求解。以中国某高纬度寒冷地区作为算例,对比了重力储能、电池储能、压缩空气等不同储能形式的优化结果,证明了从长远角度考虑高寒地区重力储能的优越性。

风火储氢碳多能耦合打捆送出模式研究

[目的]为在通道建设空间受限的情况下坚实城市负荷中心能源供给保障并实现海上风电大规模送出与消纳,提出一种风火打捆、多元耦合的系统建设运行模式,并结合项目对该模式进行理论分析与仿真验证。[方法]在研究过程中,设置风火分别送出、风火打捆送出但运行不耦合、风火打捆送出且运行耦合、风火氢碳耦合送出4种仿真试验方案,并依托HOMER软件环境及粒子群算法对试验方案进行系统运行仿真与指标测算。[结果]测试结果表明:通道总规模在未采用风火打捆送出模式时比采用风火打捆送出模式时高2.2 GW,通道平均利用率59%,比采用风火打捆送出模式时低21%~23%;风电与火电共用送出通道但运行不协同产生弃风量合计164 GWh;风火建设打捆且运营协同时可实现零弃风,并减少单位供电碳排放下降30~33 g/MWh。[结论]风火打捆、多元耦合的绿电送出及系统运行方式可行且有效,对海上风电项目的规划建设具有指导意义。

CO_(2)Plume Geothermal(CPG)Systems for Combined Heat and Power Production:an Evaluation of Various Plant Configurations

CO_(2) Plume Geothermal(CPG)systems are a promising concept for utilising petrothermal resources in the context of a future carbon capture utilisation and sequestration economy.Petrothermal geothermal energy has a tremendous worldwide potential for decarbonising both the power and heating sectors.This paper investigates three potential CPG configurations for combined heating and power generation(CHP).The present work examines scenarios with reservoir depths of 4 km and 5 km,as well as required district heating system(DHS)supply temperatures of 70℃ and 90℃.The results reveal that a two-staged serial CHP concept eventuates in the highest achievable net power output.For a thermosiphon system,the relative net power reduction by the CHP option compared with a sole power generation system is significantly lower than for a pumped system.The net power reduction for pumped systems lies between 62.6%and 22.9%.For a thermosiphon system with a depth of 5 km and a required DHS supply temperature of 70℃,the achievable net power by the most beneficial CHP option is even 9.2%higher than for sole power generation systems.The second law efficiency for the sole power generation concepts are in a range between 33.0%and 43.0%.The second law efficiency can increase up to 63.0%in the case of a CHP application.Thus,the combined heat and power generation can significantly increase the overall second law efficiency of a CPG system.The evaluation of the achievable revenues demonstrates that a CHP application might improve the economic performance of both thermosiphon and pumped CPG systems.However,the minimum heat revenue required for compensating the power reduction increases with higher electricity revenues.In summary,the results of this work provide valuable insights for the potential development of CPG systems for CHP applications and their economic feasibility.