电力变压器经济运行浅析

变压器作为输配电系统的广泛应用中电压交换设备,节能潜力巨大,本文通过分析其损耗类型及产生原因,针对其空载损耗和负载损耗分别提出了降损节能的具体措施,对生产实践有指导意义。     

配电网络技术降损措施分析与研究

降低配电网络线损率是提高电能利用率的重要措施,本文从配电线路及变压器的技术降损措施对减少10 kV配电网的电能损耗进行了分析.分析表明改造配电线路结构,提高电压等级,合理分配有功和无功潮流,采用低损耗变压器,加大导线截面,调整线路布局,合理进行无功功率补偿等具有较好的降损效果.     

电力市场环境下网损分摊方法研究

该文基于经济学边际原理和方法论思想，在综合考虑用户和电网拥有者双方利益的前提下，建立电力网络损耗分摊的数学模型，推导出一类网损分摊方法，并统一解释了现有的几种方法，通过进一步实例分析指出各种方法中存在的合理与不合理之处。     

谈农村电网的无功补偿

经过几年大规模的农网改造,农村的电网线损率明显降低。客观上,农村电网处于电力系统的未端,无功电源先天不足,农电负荷又大量消耗无功,农村电网无功比较缺乏。农村线路功率因数普遍偏低是导致高低压线路损耗大,局部地区未端用户电压低的原因之一。线损过大直接关系到电力部门及用户的经济利益;功率因数低,电网电压低,危害电网和设备安全运行增加网损,电压合格率降低,虽然调整主变电压分接也能够升高电网电压,但仍不能解决充分补偿电网无功和功率因数低的问题,这种情况在运行中的农村小型化变电所较普遍。     

调整电压和无功补偿实现节能的措施

分析功率因数、电压损失和功率损耗的关系,详细阐述供电系统通过调整电压和无功补偿等措施减少电压损失和降低线路、变压器损耗,保证供电质量和电气节能的措施.     

变压器铁损分析测量

简述了变压器的损耗产生的原因，应用电磁场理论详细计算了变压器铁损与磁场、频率的关系，分析了磁场、频率和材料对损耗的影响，为变压器的设计制作提供了一定的理论依据。并介绍了铁损简单的测量方法。     

探讨农网10kV配电线路的节能降耗

文章主要针对农网10kV线路的网损和线路运行电压的关系展开讨论,分析了怎样才能更好的降低网络损耗,提高经济效益,并对10kV出线端口加装调压装置来节能降耗提出了构想。     

配电变压器的损耗分析及其降损措施

配电变压器主要运用于农村电网和城市配网。农村负荷在夏、秋两季农忙季节用电量大,具有季节性强,用电峰谷差大、年利用小时数低等特点;城市负荷在峰谷用电量差异明显,与农村电网相比,其峰谷负荷轮换更加频繁,对供电可靠性的要求亦更高。因此合理选型和调整配电变压器容量,提高配电变压器平均负载率,是城、农配电网络降损节能的重要途径之一。本文通过配电变压器的损耗分析,提出一种新颖的有载调容变压器能够在不间断供电的情况下调节容量,从而降低配电变压器损耗。     

供电线路电源额定电压初探

研究了供电线路的损耗与电压的关系以及提高电力系统额定电压的意义。     

基于PSASP的同煤电网最优潮流分析

以大同煤矿电网经过多年的改造与扩建,虽已经形成了一个完整的供电系统,但很多变电站的变压器为国家73标准和86标准变压器,导致大同煤矿供电系统网损过高,为了降低大同煤矿电网损耗,使整个大同煤矿供电网在经济、合理的状态中运行,节约电能、降低电力成本、提高企业经济效益,利用PSASP电力系统综合仿真程序对大同煤矿电网进行潮流分析和网损分析,获得了大同煤矿电网的改造方案.通过最优潮流建模,使用PSASP建立最优潮流作业,以网损最小的目标函数进行最优潮流计算,获得最优潮流计算结果,结果表明:大同煤矿电网总有功损耗减小了3.52%,总无功损耗减小了3.48%.     

Derivations of fractal models of city hierarchies using entropy-maximization principle

A pair of models of fractal recursion on city hierarchy, fm=f1r?1-m?f and Pm=P1r?m-1?p, are derived using entropy-maximizing methods, and the relationship of inverse proportion between the number (fm) of cities at a given level of the urban hierarchy and the average population size (Pm) of the fm cities is established, i.e fm∝1/P. It is demonstrated that the underlying rationale of both the scale law of city rank-size distribution and the Zipf dimension value in standard state (dz=lnrp/lnrf=1) rests with maximization of information entropy of city hierarchies.     

块θ-方法的PLm-稳定性

讨论了带有多个滞时量的延时微分方程的数值稳定性,分析了块θ-方法求解多延迟微分方程的Pm-稳定性和兕。一稳定性的条件,证明了块θ-方法Pm-稳定的充要条件是1／2≤0≤1,块θ-方法PLm-稳定的充要条件是θ=1．     

电力变流器深控时对变流变压器设计参数的影响

从控制角α对变流电流的影响、控制角和换向重叠角与变压器阻抗的关系，得出了在深控时重叠角γ减小，导致交流电流谐波分量增加，增加了涡流损耗和附加损耗；而增大变压器阻抗可增大重叠角和减小损耗等．为设计变流变压器提供了理论依据和应用参数．     

A Study of Power Loss for 3 Phase Voltage Source Converter of Elevator

In this paper,to study the power loss of converter for elevator,The analysis is to establish relationship between parameters(current,voltages and losses in the inverter and converter) relevant for sizing of major components of the drive was done.) For high PWM(pulse width modulation) frequency like in elevator applications of fpwm =10kHz,switching losses are dominant and are about 2/3 of the total losses on IGBT switch.Transition from continuous 3 phase to discontinuous 2 phase PWM results in 50% reduction of switching loses on IGBT devices providing that PWM is not done over 60deg angle in a particular phase when current has maximum value.Total losses on IGBT(conduction + switching) are reduced approximately by ～1/3 what is still a significant reduction.Two phase PWM with reduced losses can be used for applications when acoustic noise due to increased current ripple is not significant and fall back solution to regular 3 phase PWM when drive operates under rare extreme conditions resulting in increased heat sink temperature.The analysis will be examined by further laboratory testing simulating 60% duty cycle on a dynamometer.     

电压源逆变器供电对感应电机参数的影响研究

非正弦供电的感应电机中含有谐波分量,由谐波产生的磁场常常引起电机的损耗增加、发热,并产生振动和噪声等一系列不良影响。采用谐波等效电路法来分析各种谐波对电机参数的影响,为电机工程设计提供理论依据。     

非连通图(P_1∨P_m)∪C_(4n)∪P_2的优美性

讨论非连通图(P1∨Pm)∪C4n∪P2的优美性.证明如下结论:设m、n为任意正整数,当m≥2,1≤n≤2m-2时,非连通图(P1∨Pm)∪C4n∪P2是优美图,其中Pn是n个顶点的路,G1∨G2是图G1与G2的联图,C4n是4n个顶点的圈.     

A deep seismic sounding profile across the Tianshan Mountains

The deep seismic sounding profile across the Tianshan Mountains revealed a two-layer crustal structure in the Tianshregion, namely the lower and upper crusts. Lateral variations of layer velocity and thickness are evidently shown. Low-velocity layers spread discontinuously at the bottom of the upper crust. The Moho depth is 47 km in the Kuytun area and 50 km in the Xayar area. In the Tianshan Mountains, the Moho becomes deeper with the maximum depth of 62 km around the boundary between the southern and northern Tianshan Mountains. The average velocity ranges from 6.1 to 6.3 km/s in the crust and 8.15 km/s at the top of the upper mantle. Two groups of reliable reflective seismic phases of the Moho (Pm1 and Pm2) are recognized on the shot record section of the Kuytun area. A staked and offset region, 20-30 km long, is displayed within a shot-geophone distance of 190-210 km in Pm1 and Pm2. Calculation shows that the Moho is offset by 10 km in the northern Tianshan region, 62 km deep in the south while 52 km deep in the north, and plunges northwards. In comparison with typical collisional orogenic belts, the structure of the Moho beneath the Tianshan Mountains presents a similar pattern. This can be used to explain the subduction of the Tarim plate towards the Tianshan Mountains. This intracontinental subduction is considered the dynamic mechanism of the Cenozoic uplifting of the Tianshan Mountains. The discovery of seismic phases Pm1 and Pm2 serves as the seismological evidence for the northward subduction of the Tarim plate.     

山西省地区电力调度数据网接入省网方案探讨

结合山西电力工作的实际，对地区电力调度数据网接入省网的施实方案（地区网建设方案、地区网技术规范方案、地区网接入省网方案）进行了探讨，指出该方案对山西省地区电力调度数据网络的建设，将起到规范和指导的作用。     

213树脂强碱基比例变化对其性能影响的研究

研究了 2 1 3型树脂强弱碱基比例与其性能的关系及其红外光谱分析 ,对 2 1 3的合成及应用具有参考价值。     

配电网重构与电容器的配置

配电网与输电网不同，一般是辐射型树状结构，其支路参数中Ｒ与Ｘ相差不大，有时甚至Ｒ＞Ｘ．必须采用特殊的潮流分析方法．利用配电网络重构的改进支路交换算法进行快速求解，增加了电客器配置功能以提高结点的电压，既解决电压越限问题，同时又进一步降低网损．在网络重构的实际运行约束下，以补偿电容为控制量，母线电压为被控量，利用线性规划法求解电容器配置问题．算法简单实用，可用于离线环境．