Influential Factors on Deicing Performance of Electrically Conductive Concrete Pavement

The deicing experiment of carbon fiber reinforced electrically conductive concrete （CFRC） slab was conducted in laboratory at first, then the deicing process of CFRC parement was analyzed by means of finite element method （FEM）. At last, based on the energy conservation law and the computing restdts of finite element method, the influential factors including the setting of electric heating layer, environmental temperature, the thickness of ice, material parameters, and deicing power on deicing performance and energy consumption were discussed.

Optimisation of Electrical Distribution System by Using Solar Thermal Powered Systems and Its Impact on Electrical Distribution Feeders

In this research, the performance of the solar thermal powered systems (STPS) is analyzed with different models (without inserts, with inserts and with Nano fluids with different concentrations) and its impact on the Electric load in a residential/Institutional Electrical Distribution system. For this purpose, the electrical and solar thermal water heater is tested and validated. Solar thermal powered systems and its impact on the Institutional electrical distribution feeders are tested and compared with the energy efficiency (EE) and cost optimization. The goal of this paper is to analyze the impact of solar thermal energy on electrical energy consumption in the electrical distribution feeder level. The electrical system cost and energy consumptions are tabulated and observed that there is a considerable savings.

A new method of electric energy metering considering harmonic responsibility

Aiming at the shortcomings of the existing electric energy metering method,combining with the harmonic responsibility analysis model based on the reference impedance method and the idea of apparent power decomposition in IEEE Std 1459-2010 standard,two new metering indicators—billing active power and billing power factor are defined.A new electric energy metering method is proposed and its specific implementation steps are given.The simulation model is built in Matlab/Simulink,and three different examples are set up.Using the simulation data,the various metering indicators need to be examined by the existing electric energy metering method and the new electric energy metering method are calculated.The calculation results show that the new electric energy metering method not only overcomes the shortcomings of the existing electric energy metering method,but also is very easy to be popularized and applied.

Assessment of the Wind Energy Potential of Two Burundian Sites

1-year hourly wind speed data from two Burundian stations, namely Bujumbura and Muyinga, have been processed in this work to bring an efficient help for the planning and installation of wind energy conversion systems (WECS) at those localities. Mean seasonal and diurnal variations of wind direction and wind shear exponent have been derived. Two-parameter Weibull probability density functions (PDFs) fitting the observed monthly and annual wind speed relative frequency distributions have been implemented. As shown through three complementary statistical tests, the fitting technique was very satisfactory. A wind resource analysis at 10 m above ground level (AGL) has led to a mean power density at Bujumbura which is almost thirteen fold higher than at Muyinga. The use of the empirical power law to extrapolate wind characteristics at heights from 150 to 350 m AGL has shown that energy potential of hilltops around Muyinga was only suitable for small, individual scale wind energy applications. At the opposite, wind energy potential of ridge-tops and hilltops around Bujumbura has been found suitable for medium and large scale electricity production. For that locality and at those heights, energy outputs and capacity factors (CF or Cf) have been computed for ten selected wind turbines (WTs), together with costs of electricity (COE) using the present value of cost (PVC) method. Amongst those WTs, YDF-1500-87 and S95-2.1 MW have emerged as the best options for installation owing to their highest CF and lowest COE. Moreover, an analysis of those two quantities at monthly basis for YDF-1500-87 WT has led to its best performance in the dry season. Compared to the average present COE of household hydroelectricity consumption, results of this study have evidenced economical feasibility and benefit of WECS setting in selected Burundian sites in order to supplement traditional electricity sources.

On Some Issues of Assessing the Efficiency of Renewable Energy Power Plants and the Share of Renewables in the World＇s Electricity Generation

The paper considers some issues related to the evaluation of power plants using renewable energy sources： energy efficiency, economic efficiency, the share of renewable energy in the world＇s electricity generation. At one time in the world there was a myth that more energy is expended on the construction of wind and photoelectric power stations, than they produce for the service life. Adherents of this myth are still found in Russia. In response to this myth, numerous studies have been carried out for the manufacturers of wind turbines and photovoltaic modules. It was proved that these power plants spent energy on them are produced within a period of less than a year and the energy consumed by them cannot be taken into account, since it is renewable. The author showed that power plants on organic fuel and existing nuclear plants using depleted fuel with a coefficient less than unity fundamentally cannot compensate for the energy used during their construction. In the world, the concept of the LEC （Levelized Energy Cost） produced by any power plant is widely used to estimate economic efficiency. However, the formula for determining it, in the author＇s opinion, contains an inaccuracy, which is proposed to be eliminated. At present, there are different opinions on the role of RES （Renewable Energy Sources） in the production of electricity. A summary indicator is the share of renewable energy in the world＇s electricity generation. The determination of the actual share of RES and the forecast of its growth is of significant importance for the development of the world economy. The author shows the differences in the estimates and suggests an approach for establishing agreed estimates.

Automatic Generation Control Strategy Based on Balance of Daily Electric Energy

An automatic generation control strategy based on balance of daily total electric energy is put forward. It makes the balance between actual total generated energy controlled by automatic generation system and planned total energy on base of area control error, and makes the actual 24-hour active power load curve to approach the planned load curve. The generated energy is corrected by velocity weighting factor so that it conducts dynamic regulation and reaches the speed of response. Homologous strategy is used according to the real-time data in the operation of automatic generation control. Results of simulation are perfect and power energy compensation control with ideal effect can be achieved in the particular duration.

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。

考虑电力市场化交易的电碳表计量及实现方法研究

电力间接碳排放是电力用户碳排放的主要来源之一,碳排放流是计算电力间接碳排放的重要方法。目前,基于碳排放流的计量理论尚未考虑电力市场化交易的影响,缺乏相应工程应用的实现方法,参与电力市场化交易的用户难以准确获得其用电量所对应的间接碳排放量。为解决这一难题,该文研究碳排放流理论的分布式电能实现方法,考虑电力市场化交易对交易双方及相关用户碳排放因子的影响,提出含电力市场化交易的电力系统源、网、荷全过程电碳排放量计量方法;并研究存在绿电交易、储能等情况下的电碳排放因子特点及计算方法。基于上述理论,研制了电碳表及其相关系统,并利用电碳表系统对某地电网部分实际拓扑进行分析,验证了所提方法的有效性及电碳表的实用性。

计及动态碳排放因子的多H_(2)-IES双层优化运行方法

在“双碳”目标背景下,能源系统的低碳转型是其未来的发展方向.近年来,高热值、低污染的氢能受到广泛重视.基于碳排放流理论提出一种计及动态碳排放因子的多含氢综合能源系统(H_(2)-IES)双层优化运行模型.在上层模型中,上级能源网基于效益最优原则建立经济调度模型,确定各园区的能源价格与碳排放因子并下发给下层;在下层模型中,基于纳什谈判理论建立了多园区低碳合作运行模型,并采用自适应交替方向乘子法分布式求解,确定各园区的能源需求量并反馈给上层;所提模型在多次迭代互动中实现上下层协同优化.为了实现对多园区合作收益的合理分配,提出一种基于综合议价能力的收益分配方法.算例分析表明,该双层优化方法可实现上下层间的协同运行,同时兼顾多园区运行的低碳性与经济性,通过合理分配合作收益,保证园区参与合作的积极性.

计及电动汽车充电需求的城市配电网多场景低碳优化调度研究

【目的】随着光伏、储能、电动汽车负荷在配电网中占比不断增加,高比例新能源的波动性与不确定性给配电网低碳运行带来了巨大挑战。为了有效地减少配电网的碳排放量,【方法】提出了一种考虑电动汽车负荷充电需求的配电网低碳经济优化调度方法。首先给出了基于动态碳排放因子的配电网负荷侧碳排放量计算方法,并针对居民用户、商业用户场景,构建城市配电网多场景下的电动汽车负荷充电模型,并将电动汽车负荷充电状态作为决策变量,以调度成本和碳排放量最小为目标,对配电网进行优化调度。通过在改进IEEE-33节点配电网中进行算例分析【结果】以夏季典型日为例,在可协调SOC调度模式下,居民负荷调度成本和碳排放量相比于无序SOC调度模式分别降低了8.06%、13.92%,商业负荷调度成本和碳排放量相比于无序SOC调度模式分别降低了4.31%、4.87%。【结论】结果表明,针对不同的用户场景,对电动汽车充电负荷采用可协调SOC的充电调度方法,可以有效减小配电网的调度成本,降低配电网的碳排放量。

中国城市能源电力转型发展战略影响因素量化模型及分析

随着国家碳达峰、碳中和目标的提出,作为二氧化碳主要排放源的城市能源电力消耗,其转型面临着极大的挑战。由于影响因素的指标计算存在极大的主观差异,该文根据中国296个地级市和4个直辖市的面板数据,基于信息熵提出了中国城市能源电力转型的影响因素指标体系。为解决传统线性统计学模型对城市能源电力转型影响因素的解释存在局限性的问题,该文提出了“基于SHAP值神经网络-个体随机效应-时间固定效应的混合模型”,分析了中国城市能源电力转型战略影响因素,阐述了中国城市能源电力转型的特征,并分析了不同区域、不同发展规模等级的城市能源电力转型影响因素的差异性特征和产生原因,提出了有针对性的发展战略建议,为能源电力转型战略的制定提供了理论基础。

零碳排放下电-气综合能源系统多能负荷预测

电-气综合能源系统中多能负荷之间的耦合程度不断增加,提升了能源系统调度和运行的难度。为此,对零碳排放下电-气综合能源系统多能负荷预测方法进行了研究。分析零碳排放下电-气综合能源系统的运行架构。以气象因素为影响因子,运用灰色关联度分析法获得多能负荷与各因子的相关性。将相关性分析结果与系统历史多能负荷数据共同作为输入数据,构建基础长短期记忆(LSTM)预测模型。结合樽海鞘群算法(SSA)优化模型关键参数,获得优化LSTM预测模型,实现系统多能负荷预测。试验结果表明:冷负荷与电负荷的关联度为0.88;热负荷与电负荷的关联度为0.681;实际预测平均绝对百分误差低于0.45。该方法预测效果理想,为系统最优调度与运行规划奠定了基础。

电饭锅能效检测方法及测量结果影响因素

按照现行电饭锅能源效率计量检测规则计量技术规范,介绍了电饭锅产品能效指标检测的具体操作方法,结合安徽省近六年的电饭锅产品能效监督抽查结果,探讨了检测过程中影响电饭锅热效率、待机功率和保温能耗检测结果的因素,以及安徽省能效标识监督抽查过程中暴露出的问题,最后对当前电饭锅能效检测提出了一些建议。

考虑电力电量平衡的安全约束经济调度

智能电网调度发电计划要求能够统筹考虑安全与经济、节能与减排、效率与公平等诸多因素,以实现兼顾各方利益,满足系统安全的整体发电计划的优化决策。为此,在综合考虑节能减排、安全以及传统意义上"三公"要求的基础上,建立了考虑电力电量平衡的安全约束经济调度模型,它是以发电成本最小和合同电量偏差最小的多目标优化模型,在对各个目标进行模糊化后,将其转化为多目标滑动模型,并引入了目标函数满意度及许可度因子的概念,用以反映多个相互矛盾目标的重要程度。采用基于序列二次规划的序列线性方程组算法(QP-free算法)进行计算,计算结果表明了该方法的有效性,决策者可以通过许可度因子所提供的丰富信息进行决策,方法灵活而富有弹性,符合电网安全性和公平性要求。

考量能量裕度及权重因子的电力系统节点综合脆弱性分析

从静态能量函数模型角度出发,考虑节点当前运行状态下能量相对于电压的变化率及其运行水平与临界运行状态的距离,提出一种改进的状态脆弱性指标。基于节点的固有网络参数,应用电气介数模型构建结构脆弱性评估指标。依据节点受外界不同因素影响而表现出的节点电压水平高低程度,提出综合状态和结构且考虑两者权重因子影响的综合脆弱性评估指标,使之能更全面准确地定位系统中的薄弱环节。IEEE 30节点系统的仿真分析验证了所提指标的可行性和实用性。

低碳经济对电网负荷率特性的影响分析

为研究低碳经济的发展给电网带来的挑战,从作为电力负荷特性重要指标的电网负荷率的角度分析其与低碳经济的关系。对近年来中国电网负荷率的变化情况进行了统计分析,讨论了储能技术应用、风电、光伏发电和水电等可再生能源大规模并网和电动汽车、蓄热蓄冷空调等低碳用户规模化发展对电网负荷率的影响。以北京电网为例,应用日负荷曲线叠加的方法,定量分析了蓄冷空调和电动汽车的规模化应用对电网负荷率的影响情况。分析表明,调度的方式、低碳用户发展的程度、不同的电动汽车充电时间对负荷率的影响不同。提出了各区域电网相互协作,提高电网自身容量,合理安排电动汽车充电时间的建议。

基于等值功率因数法的含谐波源支路的电能量计量方法研究

从理论上分析谐波源对电能计量的影响,通过仿真实验加以验证。依据功率因数调整电费的办法,提出了基于基波功率因数和等值功率因数相结合的电费计量方法。分别对系统侧、线性负荷侧和非线性负荷侧的电费计量进行了讨论,得出了对非线性用户在计量基波电量的基础上,应根据等值功率因数调整其电费的收取,而对于系统和线性负荷用户,则仍采用基波功率因数调整其电费的收取的结论。

变电站能效评估指标体系及建模方法

变电站在输送电能的过程中会产生大量能耗,变电站能效评估是进行电力系统能效提升的基础。首先,分析了变电站的能效及其影响因素;然后,从电气设备性能、系统运行状态、建筑结构性能和运行环境因素4个角度构建变电站能效评估指标体系,并给出指标计算模型;采用层次分析法(AHP)求取各能效指标权重,并利用灰色关联分析法对变电站进行能效综合评估;对实际变电站数据进行仿真分析,结果表明基于灰色AHP的变电站能效评估指标及模型能够有效反映变电站的能效水平。

高能电子束辐照对有机介质电气性能的影响

研究在辐射环境下介质材料的带电与介电性能及其性能退变规律,对于应用在辐射环境下介质材料的发展具有重要意义,对于提高在辐射环境下的设备及运载工具等的可靠性与寿命具有重要应用价值。该文主要以聚四氟乙烯(PTFE)、聚乙烯(PE)、三元乙丙橡胶(EPDM)和环氧树脂(ER)为研究对象,通过实验研究了它们在经过高能电子辐射后的空间电荷分布规律;研究了PTFE和EPDM在经高能电子束辐照前后电导率γ,复介电常数ε′和ε″,介质损失角正切值tanδ等电性参数的变化规律,获得了一些有价值的研究成果。

纯电动汽车能量回馈效率特性测试分析

进行高效的能量回馈,可有效延长纯电动车辆续驶里程,而能量回馈效率受到电动机转速、制动转矩、电池组荷电状态等因素的影响。利用电动汽车动力总成性能测试试验台,测试分析电动机转速、制动转矩、电池组荷电状态及电池组温度对能量回馈效率的影响规律;讨论电动机温度对能量回馈时最大制动转矩的限制;参考实车测试数据,设定能量回馈效率特性研究工况范围,对不同电动机转速、制动转矩及电池组荷电状态下的能量回馈效率进行测试;基于实测数据构建能量回馈效率预测模型,并通过台架试验验证该模型的有效性。参考能量回馈效率模型开发控制策略,实车滑行能量回馈过程中,回收能量相对于原车控制策略提高了4.8%,这表明该模型可为高效能量回馈控制策略的制定提供参考依据。