A graphic monitoring method for electric power of VVVF hydraulic system

In order to online monitor the running state of variable voltage and variable frequency(VVVF)hydraulic system,this paper presents a graphic monitoring method that fuses the information of variable frequency electric parameters.This paper first analyzes how the voltage and current of the motor stator change with the operation conditions of VVVF hydraulic system.As a result,we draw the relationship between the electric parameters(voltage and current)and power frequency.Then,the signals of the voltage and current are fused as dynamic figures based on the idea of Lissajous figures,and the values of the electric parameters are related to the features of the dynamic figures.Rigorous theoretical analysis establishes the function between the electric power of the variable frequency motor(VFM)and the features of the plotted dynamic figures including area of diagram,area of bounding rectangle,tilt angle,etc.Finally,the effectiveness of the proposed method is verified by two cases,in which the speed of VFM and the load of VVVF hydraulic system are changed.The results show that the increase of the speed of VFM enhances its three-phase electric power,but reduces the tilt angle of the plotted dynamic figures.In addition,as the load of VVVF hydraulic system is increased,the three-phase electric power of VFM and the tilt angle of the plotted dynamic figures are both increased.This paper provides a new way to online monitor the running state of VVVF hydraulic system.

Economic Dispatch of Electrical Power System Based on the Multi-objective Co-evolutionary Algorithm

It is important to distribute the load efficiently to minimize the cost of the economic dispatch of electrical power system. The uncertainty and volatility of wind energy make the economic dispatch much more complex when the general power systems are combined with wind farms. The short term wind power prediction method was discussed in this paper. The method was based on the empirical mode decomposition (EMD) and ensemble empirical mode decomposition (EEMD). Furthermore,the effect of wind farms on the traditional economic dispatch of electrical power system was analyzed. The mathematical model of the economic dispatch was established considering the environmental factors and extra spinning reserve cost. The multi-objective co-evolutionary algorithm was used to figure out the model. And the results were compared with the NSGA-Ⅱ(non-dominated sorting genetic algorithm-Ⅱ) to verify its feasibility.

The New Brazilian Power Quality Standard and a Low Cost Device Meter

This paper presents an overview about the new Brazilian Power Quality Standard and provides a low cost device PQ meter, developed and implemented to assist the national campaign to assess the Brazilian power quality indices, unknown until now. This work contributes with the search of a low cost devices PQ meter for a cost sensitive market, and introduces the new Brazilian Power Quality Standard to the international community.

Smart Meter Development for Cloud-Based Home Electricity Monitor System

Αcloud-based home electricity data-monitoring system,which is based on an Arduino Mega controller,is proposed for monitoring the electricity consumption(electrical power)and power quality(PQ)in home.This system is also capable of monitoring the fundamental frequency and supply-voltage transients to ensure that the appliances operate in a safe operation range.The measured data(voltage and current)are transmitted through a Wi Fi device between the Arduino controller and server.The transmission control protocol(TCP)server is set up to acquire the high-data transmission rate.The server system immediately displays the calculated parameters and the waveform of the acquired signal.A comparison with a standard measurement device shows that the proposed system,which can be built at a low cost,exhibits the same functions as a factory product.

Influences of uncertainties to the generation feasible region for medium- and long-term electricity transaction

For the implementation of power market in China,medium-and Iong-term security checks are essential for bilateral transactions,of which the electricity quantity that constitutes the generation feasible region(GFR)is the target.However,uncertainties from load forecasting errors and transmission contingencies are threats to medium-and Iong-term electricity tradi ng in terms of their in flue nces on the GFR.In this paper,we prese nt a graphic distortio n pattern in a typical threegenerator system using the Monte Carlo method and projection theory based on security constrained economic dispatch.The underlying potential risk to GFR from uncertainties is clearly visualized,and their impact characteristics are discussed.A case study on detailed GFR distortion was included to dem on strate the effectiveness of this visualization model.The result implies that a small uncertainty could distort the GFR to a remarkable extent and that different line-contingency precipitates disparate the GFR distortion patterns,thereby eliciting great emphasis on load forecasting and line reliability in electricity transacti ons.

储液式CCS耦合P2G的综合能源系统低碳经济调度

为应对电转气P2G(power-to-gas)和碳捕集系统CCS(carbon capture system)在可再生能源出力不足时耦合失效的问题,考虑对常规CCS引入CO_(2)储液罐以加强P2G和CCS的耦合。首先,构建储液式CCS和P2G的耦合模型,利用储液罐将CCS捕集的CO_(2)时移至可再生能源富足时段,供P2G再利用;其次,构建储液式CCS与P2G耦合的电热气综合能源系统日前优化调度模型;最后,以北方某工业园区为例进行仿真。结果证明所提模型可以充分利用CCS捕集的CO_(2),从而获得更好的经济和环境效益。

新型电力系统中的规划运营与电力市场:研究进展与科研实践

“碳达峰、碳中和”战略目标下,能源结构清洁化—可再生能源并网比例不断提高、能源要素多元化—发输配用各环节海量灵活性资源接入两大趋势带来的挑战,对电力规划、调度运营、电力市场产生了重大影响。规划中如何综合考虑海量运行场景与多元化要素,运营中如何高效调度多样灵活性资源,市场如何设计机制激励主体提供灵活性,都是新型电力系统建设亟待解决的问题。该文从电力规划、调度运营、电力市场3个层面出发,对近年来新型电力系统中规划运营与电力市场的相关研究进展进行系统梳理,涵盖基础理论、机制设计、应用研究、系统研发等多类型研究文献。进一步从规划、调度、市场3个方面展望未来研究趋势,如新型要素接入下的电网韧性、电碳耦合调度理论与高效求解技术、辅助服务与容量市场交易品类、考虑储能等新型主体的市场交易机制等,以期为我国新型电力系统的建设提供有益参考。

基于荷-储碳流模型的电力系统双层优化调度

为减少高耗能机组出力,同时增加风电消纳能力,考虑负荷和储能两类灵活调用资源,提出基于荷-储碳放流模型的电力系统双层经济低碳优化调度方法。基于电力系统碳排放流理论,分别建立负荷和储能设备的碳排放流模型;设计考虑荷-储协同优化的低碳调度策略,在负荷侧建立基于负荷节点碳势的电-碳耦合价格需求响应模型,同时鉴于荷侧降碳调节的局限性,在储能侧建立基于碳流模型的低碳调度策略,实现荷-储协同低碳调度策略;考虑经济性和低碳性,建立包含上层经济调度、下层低碳调度的双层优化调度模型。通过改进IEEE-14节点系统对优化调度方法进行仿真验证,结果表明:提出的优化调度方法在保证经济性的同时,减少了弃风,并降低了高耗能机组出力,从而有效降低了全系统的碳排放。

Overview of condition monitoring and operation control of electric power conversion systems in direct-drive wind turbines under faults

Electric power conversion system （EPCS）, which consists of a generator and power converter, is one of the most important subsystems in a direct-drive wind turbine （DD-WT）. However, this component accounts for the most failures （approximately 60% of the total number） in the entire DD-WT system according to statistical data. To improve the reliability of EPCSs and reduce the operation and maintenance cost of DD-WTs, numerous researchers have studied condition monitoring （CM） and fault diagnostics （FD）. Numerous CM and FD techniques, which have respective advantages and disadvantages, have emerged. This paper provides an overview of the CM, FD, and operation control of EPCSs in DD-WTs under faults. After introducing the functional principle and structure of EPCS, this survey discusses the common failures in wind generators and power converters; briefly reviewed CM and FD methods and operation control of these generators and power converters under faults; and discussed the grid voltage faults related to EPCSs in DD-WTs. These theories and their related technical concepts are systematically discussed. Finally, predicted development trends are presented. The paper provides a valuable reference for developing service quality evaluation methods and fault operation control systems to achieve high-performance and high-intelligence DD-WTs.

考虑风电出力和电价不确定性的水风联合现货市场竞价策略

以风电为代表的新能源参与现货市场已是大势所趋,但出力不确定性导致其市场竞争力较弱,而电价的不确定性又进一步增大了其承担的收益风险。联合具有灵活调节能力的水电是有效的解决途径,而制定符合决策者风险意愿的竞价策略则是其中亟须解决的关键问题。为此,从价格接受者角度提出了水电联合风电参与现货市场的竞价模型。模型中采用笛卡尔积组合后的典型场景集描述风电出力、市场电价等多种不确定性,采用条件风险价值衡量不确定性导致的市场风险,并以风险因子作为决策者风险偏好纳入决策过程。通过引入0/1整数变量,将模型中的非线性函数转换为混合整数线性规划模型予以求解。以中国西南某省梯级水电站和风电场为背景,验证了模型的有效性,并进一步分析了风险偏好对竞价决策的影响。

计及电动汽车的综合能源系统多主体协同低碳经济调度

针对未充分挖掘具有源荷双重特性的电动汽车集群调度潜力以辅助电力系统低碳运行的问题,提出了计及电动汽车的综合能源系统内多主体协同低碳经济调度策略。首先,考虑综合能源系统内多主体的电能交易构建了风电主体优化运行模型、计及碳捕集与电转气系统综合灵活运行的电-热耦合系统优化运行模型以及电动汽车主体优化运行模型;其次,基于纳什谈判理论建立了综合能源系统内多主体合作运行模型,将其分解为多主体联盟效益最大化子问题和电能交易支付谈判子问题,并采用交替方向乘子法对上述两个子问题进行了分布式求解以保护各主体的隐私;最后,通过算例仿真验证了所提策略能够充分挖掘碳捕集-电转气系统和电动汽车集群支撑风电消纳实现综合能源系统碳减排的潜力,提高各主体的运行效益以及合作联盟的整体效益,有效实现综合能源系统内各主体协同互济,促进新能源消纳、提升系统低碳性和经济性。

计及改进阶梯型碳交易和热电联产机组灵活输出的园区综合能源系统低碳调度

为了进一步降低园区综合能源系统(park-level integrated energy system,PIES)碳排放量,优化热电联产(combined heat and power,CHP)机组出力的灵活性,提出一种考虑改进阶梯型碳交易和CHP热电灵活输出的PIES低碳经济调度策略。首先,将遗传算法与模糊控制相结合,设计一种遗传模糊碳交易参数优化器,从而对现有阶梯型碳交易机制进行改进,实现该机制参数的自适应变化;其次,在传统CHP中加入卡琳娜(Kalina)循环与电锅炉(electricboiler,EB),构造CHP热电灵活输出模型,以同时满足电、热负荷的不同需求;然后,提出一种柔性指标——电、热输出占比率,进而计算出电、热输出占比率区间,以衡量CHP运行灵活性;最后,将改进阶梯型碳交易机制和CHP热电灵活输出模型协同优化,以系统运行成本和碳交易成本之和最小为目标,构建PIES低碳经济优化模型。算例分析表明,所提策略可有效降低经济成本和碳排放量,同时还可扩展CHP灵活输出调节范围,能够为PIES低碳经济调度提供参考。

风光储联合发电站与电力用户的电能直接交易模型

随着可再生能源和负荷预测精度的不断提升,风光储联合发电站和电力用户之间的电能直接交易具有了可行性。文章建立了风光储电站和电力用户之间电能直接交易的消纳模型。该模型以社会总效益最大化为目标,在传统模型的基础上,加入直购电合同中的电功率约束和储能相关运行约束,同时对于签订的总合同电量约束做出调整,并加入过网费和削减合同,惩罚权衡直购电量给系统带来的综合效益。结合生成的场景聚类,通过算例分析了风光储电站的日前优化结果,研究了合同电量限制因子、惩罚因子对直购电量和总社会经济效益的影响,结合纳什议价模型分析直购电价对利润均衡度的影响,验证了模型的实用性与有效性。

德国电力系统转型对我国新能源发展运行的启示

德国能源转型起步早,2022年可再生能源装机容量占总装机容量之比达到了55%,在全世界处于领先地位。德国能源转型主要依靠发展新能源,德国能源转型过程中,其电力系统运行方式、电力市场交易和管理模式方面对我国新能源发展具有重要的借鉴意义。首先从管理、运行和基础设施3方面梳理德国电力系统发展的情况及主要特点;然后归纳了德国电力市场的交易机制和新能源参与市场模式;进而在新能源并网运行管理、技术标准制定、发电功率预测及市场机制4个方面,开展中国与德国对比分析;最后结合我国电网运行的实际情况,总结出未来新能源发展与运行的启示。

欧洲大范围跨国电力互联在极端天气下电力安全保供中的作用分析

随着全球气候变化不断加剧,极端天气对电力系统的影响日益增强,电网在电力安全保供中发挥的作用愈发受到关注。欧洲电网作为世界上规模最大的跨国互联电网,其在极端天气下的电力安全保供中发挥的作用值得研究借鉴。首先,对欧洲电网跨国互联进程、跨国电力配置、跨国互联目的进行梳理,并从电力交易与调度的关系、跨国电网耦合机制、跨国输电通道容量分配机制等角度分析欧洲跨国电网的交易与调度特征。其次,以2022年夏季极端高温干旱天气下的欧洲电力供应紧张事件为例,从电量余缺互济、平衡资源共享、统一电力市场支撑、可再生能源消纳等方面分析欧洲跨国互联电网在电力安全保供中发挥的“四个平台”作用。然后,对欧洲跨国互联电网面临的问题进行剖析。最后,提出对中国电网发展的思考及建议。

虚拟电厂落地适应性分析——以阿荣旗奶源基地为例

为研究增设虚拟电厂对阿荣旗奶源基地电网改造的适应性,首先基于虚拟电厂的演进趋势以及我国发展现状,提出一套针对合约型向市场型转型的两阶段虚拟电厂运行优化模型,并基于实际情况选定两阶段的控制设备分别为电锅炉和蓄电池储能进行最优调度仿真。其次基于仿真结果,分析一阶段合约型虚拟电厂中电锅炉作为价格型负荷侧响应的经济收益,以及二阶段市场型虚拟电厂中储能对系统削峰填谷的意义。最后,通过对比虚拟电厂和扩建变电站的传统方案在系统运行稳定性和经济性上的差异,得到“虚拟电厂可以作为响应电力体制改革和清洁能源转型过渡阶段的有效思路”的结论,并根据分析结果对虚拟电厂在现阶段的实际规划和发展提出了建设性意见。

电动汽车与电力—交通耦合网互动:综述与展望

随着电动汽车的广泛普及,交通电气化程度不断上升,配电网与交通网呈现出深度耦合的趋势。实现电动汽车与电力—交通耦合网间的高效互动,可有效提升电网运行稳定性,并缓解交通网的拥堵,因此,其成为电力系统和电动汽车领域研究的热点。全面介绍电力—交通耦合网的基本概念,并深入探讨3个关键领域:电力—交通网耦合系统建模和状态预测、两网耦合下的EV充电站规划以及两网耦合下的优化调度与控制,并分析其标准体系建设状况,对其未来的发展方向提出前瞻性的展望。

一种用于输电线路视频监测的取能电源的设计

供电电源是保证高压输电线路在线监测装置稳定运行的关键,文中提出了一种基于高压电场感应取能技术的取能电源,并分别对其功率电路和控制电路进行分析设计。感应极板产生的位移电流作为取能电源的输入,直接决定着取能电源的输入功率,文中利用Comsol软件研究了感应极板尺寸对位移电流的影响,确定了感应极板的尺寸,并和实测数据进行对比,验证了仿真的正确性。基于此,文中研制了一套视频监测装置,通过感应极板和取能电源实现装置的自取能,拍摄输电线及周围环境视频并发送到远程终端。最后,通过实验确定了当视频监测装置应用在110 kV电压等级下时,远程终端接收到的单次视频时长为2.2 min,视频间隔为54.9 min。