购电量和电量结构对售电公司购电策略的影响分析

售电公司作为参与电力市场化交易的主体,如何确定购电策略是其运行的关键问题。本文研究了价差套利模式下,购电量和电量结构对售电公司的影响,并为售电公司的经营策略提供相关建议。

火力发电企业电量结构创新探索

经济增长是用电量增长第一驱动力,进入21世纪以来,电力市场面临着巨大的冲击,尤其是在全球金融危机的影响下,电力行业所面对的机遇和挑战也变得更多。大火电机组燃煤效率高,具备成本低、效率高、稳定性强等多重优势,所以火电长期仍将作为主力电源,火电成本仍具优势。火力发电厂在电力供给行业中占据主导的地位,其电量结构也随着市场经济的变革和创新不断优化。本文分析了火力发电企业电量结构在经营创新过程中发生的变化,不断探索火力发电企业经营供给的最优方式。

浅析青海电力市场客户用电量结构

文章通过对目前青海电力市场客户用电量结构的分析,提出了适应青海电力销售市场发展的一种有效途径,即把提高城乡客户用电量作为青海电力公司发展的空间,同时对造成城乡客户用电量少的原因进行分析,提出了针对性措施。

基于风电时域特性分析的购电量研究

近几年随着新能源的不断发展,风电并网所带来的各种问题成为人们研究的热点。辽宁电网作为连接东北电网和华北电网的电力通道,既要满足本省电力供需平衡,又要将吉林、蒙东等多余电力输送出去,为提高电网运营效益和保障电网安全,建立了风电并网时域特性分析模型,分析了风电并网对公司购电量结构的影响,给出了不同时段公司购电量的结构比例,为公司运营决策提供技术支持。

电力市场售电公司最优购售电量决策模型及其应用

2021年中国电力中长期市场重签年度合同的现象,凸显了市场主体考虑风险因素的最优电量组合决策的理论及政策问题。在自主决策批发市场购电量和零售市场电价套餐的前提下,构建售电公司基于条件风险价值(CVaR)的购、售电业务最优电量比例的决策模型,并进行实例计算及分析。根据目前省级电力市场实际设计售电公司的典型购售电业务情景,提出相应的收入或成本计算方法;以条件风险价值为风险评估指标,以批发市场不同交易品种购电量比例和零售市场不同电价套餐售电量比例为决策变量,以收益最大为优化目标,建立售电公司收益—风险最优决策模型。结合广东电力市场实际数据计算典型购售电业务组合与置信水平对于售电公司购售电电量结构、收益及风险的影响。通过模型构建与模拟计算合理解释和分析重签合同的原因,为包括售电公司在内的市场主体考虑风险管理的购售电量决策和政府年度市场交易方案制定提供依据。

基于概率预测的用电采集终端电量异常在线实时识别方法

电力市场环境下用电信息采集系统采集的用电量成为市场结算的重要依据。实时识别用电采集终端上送的异常电量,不但可以提升数据质量,也可以为发现采集终端的故障、识别异常用电行为提供参考。针对现有异常数据识别方法识别性能和实时性不高的问题,提出基于概率预测的电量异常在线实时识别方法。首先,在分析电量异常类型和特点的基础上,提出离线训练概率预测模型、在线实时识别异常数据的检测方法。其次,提出了基于状态空间模型的结构化用电量模型对用户用电规律进行建模,并采用变分贝叶斯推断训练模型,以实现用电量的概率分布预测。最后,利用预测标准分数衡量电量实测数据与电量概率预测结果之间的差异,从而实现异常数据的在线识别。采用实际电量数据进行验证,并与其他方法进行对比,验证了该方法的实用性和有效性。

基于关口点电价的购电成本分析

当前电网的经营正从精细化管理向精益化管理转变,但是相关人员缺乏有效工具来跟踪购电成本变化并进行相关分析,严重影响了电力交易的灵活性与时效性。为解决这一不足,及时动态获取当前时刻的购电单价,简化电价变化的相关因素分析,以满足电网公司的精益化管理需求,建立了一种关口点电价信息的购电成本与单价分析模型,并应用全微分方程分析了该模型的合理性与灵敏度,开发的关口信息管理平台应用,表明该模型可有效提升公司经营管理的可控、能控、在控能力,也证明了该模型的实用性。

上海市电力供需状况分析

1、上海电力供需现状及其形势分析 1.1 2003年本市用电需求分析 2003年本市统调用电量完成732.67亿千瓦时,同比净增98.83亿千瓦时,增长15.6%.最高日用电量27840万千瓦时(8月27日),同比净增3234万千瓦时,增长13.1%.

跨流域调水工程的发电影响分析模型研究

为研究跨流域调水工程对下游流域梯级水电站群的发电量及电量结构影响,选取梯级电站枯水期最小出力最大化及年发电量最大两个目标,建立了跨流域调水工程的发电影响分析模型,采用逐步优化算法求解模型,并以西南地区的跨流域调水工程为例,研究“年内均匀调水”方式和“丰水期多调枯水期少调”方式的梯级电站年发电量及其结构影响。结果表明,随着来水频率的增加,两种调水方式对梯级电站的年发电量影响逐渐增大,平、枯、特枯年份两种调水方式的电量损失比例分别为6.59%、8.03%、10.14%和6.08%、6.97%、8.24%;“年内均匀调水”方式对枯水期的发电影响较大,相较于“丰水期多调枯水期少调”方式会进一步加剧西南水电大省在电力供应方面的“丰裕枯缺”矛盾;该模型可为跨流域调水工程论证决策提供技术支持。

Beryllium-distribution in metallic glass matrix composite containing beryllium

The morphologies, sizes, compositions and volume fractions of dendritic phases in in situ Ti-based metallic glass matrix composites （MGMCs） containing beryllium （Be） with the nominal composition of Tia7Zr19Cu5V12Be17 （mole fraction, %） were investigated using XRD, SEM, EBSD, TEM, EDS and three-dimensional reconstruction method. Moreover, visualized at the nanoscale, Be distribution is confirmed to be only present in the matrix using scanning transmission electron microscopy-electron energy loss spectroscopy （STEM-EELS）. Based on these findings, it has been obtained that the accurate chemical compositions are Wi28.3Zr19.7Cu8V6.4Be37.6 （mole fraction, %） for glass matrix and Wi62.nZr18.aCu2.6V16.6 （mole fraction, %） for the dendritic phases, and the volume fractions are 38.5% and 61.5%, respectively. It is believed that the results are of particular importance for the designing of Be-containing MGMCs.

Material Growth and Device Fabrication of GaN-Based Blue-Violet Laser Diodes

Studies on first GaN-based blue-violet laser diodes(LDs) in China mainland are reported.High quality GaN materials as well as GaN-based quantum wells laser structures are grown by metal-organic chemical vapor deposition method.The X-ray double-crystal diffraction rocking curve measurements show the full-width half maximum of 180″ and 185″ for (0002) symmetric reflection and (10 12) skew reflection,respectively.A room temperature mobility of 850cm2/(V·s) is obtained for a 3μm thick GaN film.Gain guided and ridge geometry waveguide laser diodes are fabricated with cleaved facet mirrors at room temperature under pulse current injection.The lasing wavelength is 405 9nm.A threshold current density of 5kA/cm2 and an output light power over 100mW are obtained for ridge geometry waveguide laser diodes.

基于关口计量平台的购电单价和购电成本分析

为提高电网公司的经营管理水平,利用辽宁电网设计开发的关口信息管理平台,建立了一种基于关口点电价信息的购电成本与单价分析模型,并应用全微分关系分析了该模型具有的预测性。通过实例证明了它的有效性和实用性,其应用可提升公司经营管理工作可控、能控、在控的能力。

Model experiment of rock blasting with single borehole and double free-surface

In order to improve the quality of laneways and tunnel excavation by drilling and blasting and by making effective use of explosive energy, a model experiment of rock blasting with a single borehole and a double free-surface was performed with the objective of studying the effect of parameters such as charge structure, free-surface and rock compressive strength on rock blasting.The model experiments indicate that:1) the smaller the rock compressive strength and density, the more distinctive the cavity expanding action by blasting;2) the powder factor in an air-decoupling charge structure is larger than that in a coupling charge structure, i.e., the explosive energy in an air-decoupling charge structure transferred to the rocks is less than that in a coupling charge structure;3) a free-surface improves the utilizations of explosive energy;4) an air-decoupling charge structure helps to maintain the integrity and stability of wall rock in controlled perimeter blasting, such as in roadways and tunnel excavation by drilling and blasting.

First-Principle Studies on Conductive Behaviors of P-Type ZnO Codoped by N and B

Using a first-principle method, the electronic structures and the impurity formation energy of ZnO, ZnO （N）, ZnO （N＋B）, and ZnO （2N＋B） have been calculated, based on which the feasibility to obtain p-type ZnO ＆ discussed. According to the results, when ZnO is single doped by N, the acceptor level is deep, and the formation energy is negative, so the ideal p-type ZnO can not be obtained by this way. On the contrary, when 2N＋B are codoped into ZnO, the acceptor level becomes much lower, and the formation energy is positive, so it is a better way to obtain p-type ZnO.

Effective Pyroelectric Coefficient and Polarization Offset of Compositionally Step-like Graded Ferroelectric Structures

In this paper, the effective pyroelectric coefficient and polarization offset of the compositionally step-like graded multilayer ferroelectric structures have been studied by use of the first-principles approach. It is exhibited that the dielectric gradient has a nontrivial influence on the effective pyroelectric coefficient, but has a little influence on the polarization offset; and the polarization gradient plays an important role in the abnormal hysteresis loop phenomenon of the co.mpositionally step-like graded ferroelectric structures. Moreover, the origin of the polarization offset is explored,which can be attributed to the polarization gradient in the compositionally step-like graded structure.

Effects of Na content on structure and electrochemical performances of Na_xMnO_(2+δ) cathode material

Sodium manganese oxides,NaxMnO2+δ(x = 0.4,0.5,0.6,0.7,1.0;δ = 0-0.3),were synthesized by solid-state reaction routine combined with sol-gel process.The structure,morphology and electrochemical performances of as-prepared samples were characterized by XRD,SEM,CV,EIS and galvanostatic charge/discharge experiments.It is found that Na0.6MnO2+δ and Na0.7MnO2+δ have high discharge capacity and good cycle performance.At a current density of 25 mA/g at the cutoff voltage of 2.0-4.3 V,Na0.6MnO2+δ gives the second discharge capacity of 188 mA·h/g and remains 77.9% of second discharge capacity after 40 cycles.Na0.7MnO2+δ exhibits the second discharge capacity of 176 mA·h/g and shows better cyclic stability;the capacity retention after 40 cycles is close to 85.5%.Even when the current density increases to 250 mA/g,the discharge capacity of Na0.7MnO2+δ still approaches to 107 mA·h/g after 40 cycles.

LARGE VOLUME IONIZATION CHAMBER USED AS LABORATORY REFERENCE FOR LOW ENERGY X－RAY MEASUREMENT

A large volume spherical ionization chamber of 195 mm diameter and 0.36 mg/cm2wall thickness made from conducting carbon-fibre epoxy composite material has been developed. The mechanical intensity of the chamber is satisfactory for a good longterm volume stability. Owing to its large volume and thin wall, the chamber is sensitive to low energy photon beams and has excellent energy-response characteristics. This ionization chamber is suitable not only for a laboratory reference but also for measurement of low energy photon beam exposure rates at protection-level.

Synthesis and electrochemical performance of Li_2Mg_(0.15)Mn_(0.4)Co_(0.45)SiO_4/C cathode material for lithium ion batteries

The synthesis, structure and performance of Li2Mg0.15Mn0.4Co0.45SiO4/C cathode material were studied. The Li2Mg0.15Mn0.4Co0.45SiO4/C solid solution with orthorhombic unit cell （space group Pmn21） was synthesized successfully by combination of wet process and solid-state reaction at high temperature, and its electrochemical performance was investigated primarily. Li2Mg0.15Mn0.4Co0.45SiO4/C composite materials deliver a charge capacity of 302 mA-h/g and a discharge capacity of 171 mA.h/g in the first cycle. The discharge capacity is stabilized at about 100 mA-h/g after 10 cycles at a current density of 10 mA/g in the voltage of 1.5-4.8 V vs Li/Li^＋. The results show that Mg-substitution for the Co ions in Li2Mn0.4Co0.6SiO4 improves the stabilization of initial structure and the electrochemical nerformance.

Three-dimensional forward modeling for the SBTEM method using an unstructured fi nite-element method

In this study,we propose a three-dimensional(3D)forward modeling algorithm of surface-to-borehole transient electromagnetic(SBTEM)fields based on an unstructured vector fi nite-element method to analyze the characteristics of SBTEM responses for complex geoelectrical models.To solve the double-curl diff usion equation for the electric fi eld,we use an unstructured tetrahedral mesh to discretize the model domain and select the unconditionally stable backward Euler scheme to discretize the time derivative.In our numerical experiments,we use a grounded wire as a transmitting source.After validating the algorithm’s eff ectiveness,we first analyze the diffusion characteristics and detectability of the electromagnetic field.After that,we focus our attention on the distribution and the cause of zero bands for Ex and dBy/dt components with the hope of guiding future field surveys.Finally,by simulating diff erent models,we analyze the capability of the SBTEM method in detecting typical mineral veins so that we can provide a reference for mineral resource exploration in the deep earth.

Electrode heating effects on preparation of Al-65V alloy

In this study,Al-65V alloy has been produced by electrode heating for 3−15 min.The impurities content,microstructure and the vanadium content of the alloy in the slag are investigated.The results indicate that different heating time shows obviously impacts not only on the impurities and microstructure of AlV alloy,but also on the vanadium recovery rate of slag.The impurities contents of C,O and N are 0.085%,0.022%and 0.036%,respectively,which meet the commercial standard when the electric heating time is controlled to 10 min,and the content of vanadium in slag is 0.18%.