某公司变压器节能运行方式的选择实践

研究变压器的经济运行方式,在确保变压器安全运行及满足供电量并保证供电质量的基础上,充分利用现有能源计量平台,通过择优选取变压器最佳运行方式、负载调整的优化,确定变压器运行最佳方式,从而最大限度地降低变压器的电能损失,达到节能目的,实现变压器的经济运行。     

变压器经济运行技术的最新研究

现在变压器经济运行的理论都围绕变压器的经济运行点展开,希望变压器在经济运行点下运行。通过实例比较发现,有时变压器一味追求在经济运行点运行并不经济,对此提出了一种更为实际的变压器运行方式：根据不同的变压器,以及实际情况选择适当的经济负载系数,即非经济运行点运行。新的运行方式为变压器运行提供了良好的决策依据。     

2台变压器节能运行中的问题的分析

在物业服务范围内的各变配电室,都是2台变压器分段运行,多数变压器的负荷率都不高,为了节能,是否应该停用1台变压器。通过某服务处运行中变压器损耗的计算,说明停用1台变压器所节省的能耗,不是该停用变压器在使用时的损耗。停用变压器的节能效果与另一台在用变压器的负荷率关系很大。实施变压器的节能,不能只考虑负荷率的因素,必须综合考虑变压器的经济运行、供电安全性、可靠性、基本电费收费方式、变压器的使用寿命等因素。     

配电变压器经济运行自动控制投切策略研究

针对厂矿、企业内投运的2台及以上10kV配电变压器,因用电性质、季节气候引起负荷变化,变压器长时间处于空载和轻载状态,导致损耗增大的问题,提出了2台变压器并列组合优化经济运行自动控制投切方案。在变压器组合已经具备硬件自动控制的基础上,以变压器运行实时负荷参数为控制量,按照预定的经济运行策略进行自动投切,达到就地自动控制和最佳节能的运行方式,节省电能。     

配电变压器的节能管理

结合德州供电公司降低变损的实践,阐述了变压器经济运行的原理,分析介绍了变压器节能运行的方法和途径。     

三绕组变压器常见运行方式的经济性分析

本文针对两三绕组变压器常用的运行方式作了负载分配、有功损耗计算及经济性分析,给出了判断经济运行方式的判据,为运行人员安排变压器经济运行方式提供了简捷的计算公式。     

浅谈配电变压器的经济运行

介绍了企业配电变压器经济运行在节能领域中所起到的重要作用。通过理论分析和实践研究 ,认为变压器经济运行不仅是必要的而且是可行的。针对变压器综合能耗的特点对如何把日常运行中的变压器调到经济、合理的状态提出了一些具体的措施     

浅析变压器经济运行方案

通过对变压器电能损耗的分析,确定具体的经济运行方案以降低变压器损耗,达到节能降损,从而提高电网运行的经济效益。     

变压器的经济运行

从三方面讨论了变压器经济运行的优化措施;调整变压器容量,应用节能型变压器,调整变压器运行方式.并论述了变压器经济运行实施的可行性及经济效益.     

按最大需量计算基本电费有利于推广变压器的经济运行

本文通过计算变压器运行时的实际损耗,说明按最大需量计算基本电费有利于推行变压器的经济运行,符合节能要求,应予大力推广。     

500kV GIS变电站快速暂态过电压及防护措施仿真研究

根据实际GIS系统结构,利用ATP-EMTP电磁暂态程序对三种不同的快速暂态过电压（VFTO）防护措施的作用效果进行了仿真分析,即隔离开关加装并联电阻、主变入口前加装并联电容器和主变入口前加装串联阻波器。仿真结果表明,三种措施中隔离开关加装并联电阻的防护效果最为明显,不仅能够大幅度降低GIS电站中的VFTO幅值,同时还能明显减小VFTO的波前陡度,抑制VFTO的威胁;主变入口前加装并联电容器有一定的防护效果,但作用不如隔离开关加装并联电阻明显;主变入口前加装串联阻波器对减小传入主变绕组的VFTO波前陡度有较好的作用,但阻波器本身将承受幅值很高的陡波前过电压,同时还会给GIS电站引入高频谐波,不能作为防护VFTO的措施。     

A three-phase current-fed dc/dc converter with a three-leg high frequency transformer for fuel cells

In this paper, a three-phase current-fed dc/dc converter with an active clamp is introduced, and a new three-phase three-leg high frequency transformer is proposed for the converter. The three-phase dc/dc converter transfers power through transformer leakage inductances in the discontinuous current mode; a single common active clamp branch is employed for zero-voltage switching (ZVS) in all active switches. Further, the converter's three-phase power configuration increases power transfer, and it reduces the rms current per phase, thus reduces conduction losses. Moreover, a delta–delta connection on the three-phase transformer provides parallel current paths and reduces conduction losses in the transformer windings. A three-phase transformer can be constructed by connecting three discrete single-phase transformers, but this process results in a higher volume and higher material costs. Therefore, a new three-phase three-leg high frequency transformer is designed with three discrete cores integrated into a single transformer core. The proposed transformer is analyzed according to the several operating modes of the converter, and its design rules are determined. Experimental results are obtained on a 500-W prototype unit; the design is fully verified and analyzed.     

变压器自动投退的技术经济分析

以两台变压器并列运行为例,分析了变压器自动投退的技术经济情况。结果表明,在变电站运行过程中自动投切变压器,改变其运行方式,可减少变压器运行损耗,提高经济效益,为优化电网运行提供有效途径。     

变压器和应涌流及中性点零序电流分量仿真分析

简要阐述了变压器和应涌流的产生机理,并在PSCAD仿真软件中建立并联变压器和应涌流模型。通过仿真分析了变压器和应涌流波形及谐波电流特点,同时分析了变压器中性点直接接地系统零序电流产生的原因和谐波电流成分,并指出了其对继电保护产生的影响。     

多只电压互感器同步校验误差分析

针对目前省市级计量检定部门电压互感器校验量大幅增加,而校验工作人力有限的实际情况,介绍了一种能一次同步校验12只电压互感器的高效方法,分析了电压互感器误差组成,基于高端测差法设计了多只电压互感器同步校验系统接线方案,对12只电压互感器并联给标准电压互感器带来的附加误差进行了理论分析与计算,并通过试验验证了误差理论的正确性及校验方案的可行性。     

变压器经济运行负荷区间的选择

本文根据三绕组变压器经济运行理论 ,导出了变压器经济运行的负荷算式 ,并提出一套完整的算法。可用于指导变压器并列运行方式的调整 ,达到减少电能损耗的目的。     

Optimization of the fault-current limiting transformer

The fault current limiting transformer (FCLT) presented by J. Brochu et al. (see IEEE Trans. Power Delivery, vol.13, p.233-40, 1998) was designed with the purpose of increasing the total capacity of a transformer station without increasing short-circuit currents. In situations where such an IPC is closely coupled with parallel transformers, the FCLT installation can be simplified. The purpose of this letter is to describe the enhanced capabilities and outline the basic design criteria for this innovative IPC application. An application example provides typical component ratings, space requirements, and a budget cost estimate     

中频隔离型光伏±35kV/500kW直流变流器研究与工程应用

首先提出一种中频隔离型光伏±35 kV/500 kW直流变流器,该直流变流器由三相T型三电平并联中频逆变器模组、中频400 Hz/24脉波移相升压变压器、三相二极管整流桥以及高压滤波电路组成,该变流器具有升压比高、结构简单、成本低的优势;其次,为了实现逆变器并联模组有功、无功功率的实时均分,采用一种瞬时功率均分的功率主从控制方案;接着,提出一种基于中频变压器无功补偿的改进型LCL滤波器参数设计方法以提高变流器的效率。最后,通过Matlab/Simulink仿真以及张北国家大型风电并网系统研发（实验）中心建设的光伏发电中压直流汇集现场示范工程,对所提直流变流器的设计理念和控制方法进行验证,现场并网实测最大效率为96.33%,升压比高达88,输出电压±35 kV,仿真和实验结果证明了所提直流变流器的可行性。     

变压器单并运行状态下的最佳经济点

本文从电力变压器的有、无功损失方面谈最佳经济运行负载率，并研究探讨单并联状态下的经济运行切换点，最后以实例说明此问题。     

Design and analysis of a 35 kVA medium frequency power transformer with the nanocrystalline core material

Medium frequency power transformers embedded into power electronics converters are frequently encountered in many applications such as electrical transportation and renewable energy systems and power supplies. Thus, researchers have been focused on soft magnetic materials such as amorphous and nanocrystalline materials to obtain smaller and more efficient transformer designs with the improvements on manufacturing technologies of the high frequency core materials. In this study, the transformer design methodology is proposed with the finite element analysis method, and a 35 kVA medium frequency transformer with nanocrystalline core material is designed. After the sizing stage, three-dimensional model of the transformer is created with finite element analysis software, and then co-simulations of this electromagnetic transformer model with a power electronics converter circuit are performed for practical operation conditions. Furthermore, thermal behavior of the prototype transformer is determined with the thermal coupling analysis, and temperature distribution of the prototype transformer is visualized with a thermal imaging camera. The transformer efficiency, exact equivalent circuit of the transformer and flux distributions in the transformer core are obtained from these simulation studies. In addition, the prototype of the designed transformer is produced and tested. The design conditions and simulation results are validated with experimental studies.