浅谈配电变压器经济容量选择方法及其应用

随着国内外变压器制造技术水平不断提高和新型材料的应用,传统的容量选择计算方法,显然已不能完全适应配电变压器容量选择的要求。配电变压器容量选择与经济运行问题密切相关,因此进行容量选择就应当是对经济容量的选择。分析研究表明,若按照配电变压器容量选择条件,在一定的容量级差范围内,选择电能损耗量最小的容量方案,所确定的容量,即为配电变压器在经济使用期内可获得经济效益最佳的设计容量。同时根据本文得出的结论,可使经济容量选择方法进一步简化、满足方便使用的要求。     

配电变压器经济调度运行措施分析

配电变压器是电力系统中的核心设备,变压器经济运行,能够达到节能减排的效果。文章首先对变压器运行理论分析,进而提出实现变压器经济调度运行措施。     

浅析配电变压器低压并列运行的技术要点

本文主要围绕配电变压器低压并列运行方面的运用进行阐述,在形成多元化综合节能控制的基础上,形成配电变压器并列运行中电能转换效率的综合控制技术,更好的实现配网变压器的安全稳定运行。     

变压器的节能措施分析

阐述变压器损耗与经济负载率的特点,变压器的节能措施,包括变压器损耗计算、运行数据的跟踪分析、高效低损节能变压器、变压器运行方式与容量选取。     

农网配电变压器的经济运行

通过理论计算和实际分析从五个方面论述了配电变压器的经济运行是降损增效的一项车量措施。通过调整变压器的负荷、容量、分接开关、补偿电容器和更换节能变压器五个方面来降低电能的损耗，提高电网的运行效率。     

低压配电变压器节能关键技术研究

变压器是电网中最重要的电力设备,其数量多,总的电能损耗很大。据统计,配电变压器的电能损耗约占输配电系统电能损耗的30%,因此,降低配电变压器的能耗,已成为最重要最紧迫的任务之一。针对低压配电变压器的节能关键技术进行研究,分析配电变压器各种损耗的产生机理以及降低损耗的方法,对现有配电变压器运行特点和数据加以对比研究和数据挖掘,优化调整配电网运行电压和智能控制三相负荷实时平衡,实现配电变压器节能降耗经济调度运行目标,是节能降耗的重要技术,具有较大的工程实际研究意义。     

浅析调容变与子母变的应用

<正>农村用电负荷有着明显的季节性,一般最高负荷都出现在春节期间,农户会集中用电,在这种状况下,用电高峰季时与用电淡季是相差很大,高峰季时变压器过载运行严重,而在淡季是也现了"大马拉小车"的现象,造成变压器空载损耗严重,这给选择变压器容量带来了困难。按大负荷选择。变压器运行不经济,按小容量选择,高峰季节会出现设备烧坏现象,造成不必要的经济损失,为了合理选择配电变压器容量,提升10kV配电变压器的供电能力,公司推出调容     

试述工厂电气照明及配电节能

本文对工厂电气照明的原理进行了分析,探讨在电气照明工作的过程当中,关于电气照明的设置、在基础的电气照明上进行合理化修改,及配电节能的合理化设计,通过对电气照明设备的更换,和合理化布置达到配电节能的目的,同时针对于在节能过程中存在的问题进行分析,以及新型能源的有效使用,通过对各方面问题的综合分析和探讨,给出可行的电气照明和配电节能方案,最终达到工厂电气照明和配电节能的目的。     

谈小型配电变压器受潮后的短路烘干的处理步骤

本文结合作者多年基层工作经验,就农网配电变压器受潮原因进行分析,并就400kVA以下容量的配电变压器受潮后的处理步骤及注意事项进行讲解,以期对业内同仁有所借鉴.     

非晶合金配电变压器安装技术

本文分析了农网配电变压器运行现状以及阻碍非晶合金配电变压器推广应用的因素，介绍了非晶合金配电变压器的生产技术水平和应用状况，从年运行费用、效率与负载系数等情况及投资回收期限、总拥有费用等方面对非晶合金配电变压器节能效果进行了理论计算，为用户合理选用非晶合金配电变压器提供了依据。并提出用户订购以及采用非晶合金配电变压器时应注意的几点问题，并且针对相关问题给出建议。     

On the Capacity and Energy Efficiency of Training-Based Transmissions Over Fading Channels

In this paper, the capacity and energy efficiency of training-based communication schemes employed for transmission over a priori unknown Rayleigh block-fading channels are studied. Initially, the case in which the product of the estimate error and transmitted signal is assumed to be Gaussian noise is considered. In this case, it is shown that bit energy requirements grow without bound as the signal-to-noise ratio (SNR) goes to zero, and the minimum bit energy is achieved at a nonzero SNR value below which one should not operate. The effect of the block length on both the minimum bit energy and the SNR value at which the minimum is achieved is investigated. Flash training and transmission schemes are analyzed and shown to improve the energy efficiency in the low-SNR regime. In the second part of this paper, the capacity and energy efficiency of training-based schemes are investigated when the channel input vector in each coherence block is subject to peak power constraints. The capacity-achieving input structure is characterized and the magnitude distribution of the optimal input is shown to be discrete with a finite number of mass points. The capacity, bit energy requirements, and optimal resource allocation strategies are obtained through numerical analysis. The improvements in energy efficiency when on-off keying (OOK) with fixed peak power and vanishing duty cycle is employed are studied.     

环面点胶对电源磁性器件可加工性的影响

变压器、电感等磁性器件性能显著影响电源参数指标。针对E型变压器磁芯气隙制作一致性差、效率低的问题,建立了不同点胶方案的有限元分析模型,进行了高黏度环氧绝缘胶非牛顿流体的剪切力机理分析。结果表明,通过减小胶点尺寸、改变胶点形态及分布的方法,可以提高磁芯器件的一致性和加工效率。采用全自动点胶工艺精确控制胶点半径和中心距,制作出了满足电感量要求的变压器,提升了加工效率,验证了仿真和机理分析的正确性。获得了一种高精度、高效的环面点胶和磁性器件制作工艺方法。     

居住区配变容量配置的计算机辅助计算

针对目前客户经理制定居住区供配电方案时,配变容量的配置计算繁锁复杂,耗时耗力的问题,通过认真分析,研究评估,设计出了相关的计算机辅助计算工具,大大加快了计算速度,使客户经理可以更高效优化地制定居住区的供配电方案,该计算工具在公司得到了广泛的应用,值得向同行推广。     

PCB设备待机精益节能技术

在印制电路板生产设备能耗中,设备待机能耗就像吸血虫一样吸食着电费和能源,同时也制造着巨大的环保压力,这其中也蕴藏着巨大的节能潜力可以挖掘。就节能而言,结构节能是一项长期任务,管理节能要靠日积月累,从某种意义上讲,技术节能更具有实效性和突破性。文章介绍了在降低PCB设备待机能耗实践活动中,将精益生产为基础,以技术创新为核心;设备待机“零”能耗的设备节能创新管理模式。主要从减少待机功率,缩短待机时间、提升待机能效、减少待机损耗等方面入手,理论与技术创新相结合,有效的降低了设备能耗。     

聚合干扰下小小区网络的协作传输方案及性能分析

该文针对聚合干扰下小小区网络协作传输的场景,分析了宏小区基站的物理位置服从泊松分布,且多用户预编码采用线性预编码时用户端的性能。通过基于概率密度函数的性能分析法,推导出小小区网络协作传输的中断概率、容量以及误符号率的闭合表达式,结果表明由于聚合干扰的存在,仅仅依靠小小区网络基站天线数的增加并不能持续提高用户端的性能。进一步,针对小小区网络中用户的接入问题,提出了一种基于能效最大化的用户接入方案,并对所提方案进行了性能分析和仿真验证,从结果可以看到所提小小区网络用户接入方案在提高系统能效方面要优于其他接入方案,仿真结果验证了基于能效最大化的接入方案的优越性,并验证了本文理论分析的正确性。      

On the energy efficiency of MIMO cooperative relaying networks

Cooperative relaying techniques can greatly improve the capacity of the multiple input and multiple output (MIMO) wireless system. The transmit power allocation (TPA) strategies for various relaying protocols have become very important for improving the energy efficiency. This article proposes novel TPA schemes in the MIMO cooperative relaying system. Two different scenarios are considered. One is the hybrid decode-and-forward (HDF) protocol in which the zero-forcing (ZF) process is operated on relays, and the other is the decode-and-forward (DF) protocol with relay node and antenna selection strategies. The simulation results indicate that the proposed schemes can bring about significant capacity gain by exploiting the nature of the relay link. Additionally, the proposed TPA scheme in the HDF system can achieve the same capacity as the equal TPA with fewer relay nodes used. Finally, the capacity gain with the proposed schemes increases when the distribution range of relay nodes expands.     

Optimal nonuniform signaling for Gaussian channels

Variable-rate data transmission schemes in which constellation points are selected according to a nonuniform probability distribution are studied. When the criterion is one of minimizing the average transmitted energy for a given average bit rate, the best possible distribution with which to select constellations points is a Maxwell-Boltzmann distribution. In principle, when constellation points are selected according to a Maxwell-Boltzmann distribution, the ultimate shaping gain (πe/6 or 1.53 dB) can be achieved in any dimension. Nonuniform signaling schemes can be designed by mapping simple variable-length prefix codes onto the constellation. Using the Huffman procedure, prefix codes can be designed that approach the optimal performance. These schemes provide a fixed-rate primary channel and a variable-rate secondary channel, and are easily incorporated into standard lattice-type coded modulation schemes     

On the energy efficiency of base station cooperation under limited backhaul capacity

Recently, energy-efficient (EE) communications have received increasing interest specially in cellular networks. Promising techniques, such as multiple input multiple output (MIMO) and base station (BS) cooperation schemes, have been widely studied in the past to improve the spectral efficiency and the reliability. Nowadays, the purpose is to investigate how these techniques can reduce the energy consumption of the systems. In this paper, we address for a single-user scenario, the energy efficiency of two BSs cooperation under limited backhaul capacity. In order to evaluate the EE metric, we provide first an information-theoretical analysis based on the outage probability, for a quantization model over the backhaul. Then, we extend this EE analysis to a more practical approach with data transmission over the backhaul. For both approaches, we identify by numerical/simulation results the cooperation scenarios that can save energy depending on the backhaul capacity.     

Energy efficiency of some non-cooperative, cooperative and hybrid communication schemes in multi-relay WSNs

In this paper we analyze the energy efficiency of single-hop, multi-hop, cooperative selective decode-and-forward, cooperative incremental decode-and-forward, and even the combination of cooperative and non-cooperative schemes, in wireless sensor networks composed of several nodes. We assume that, as the sensor nodes can experience either non line-of-sight or some line-of-sight conditions, the Nakagami-m fading distribution is used to model the wireless environment. The energy efficiency analysis is constrained by a target outage probability and an end-to-end throughput. Our results show that in most scenarios cooperative incremental schemes are more energy efficient than the other methods.     

A Practical Approach to Energy Efficient Communications in Mobile Wireless Networks

Energy efficiency and capacity maximization are two of the most challenging issues to be addressed by current and future cellular networks. Significant research effort has been placed recently in reducing the total energy consumption while maintaining or improving capacity either by introducing more efficient hardware components or by developing innovative software techniques. In this paper we investigate a novel networking paradigm to address the aforementioned problems. By capitalizing on the inherent delay tolerance of Internet type services, we argue that significant energy savings can be achieved by postponing the communication of information for a later time instance with better networking conditions. We device decentralized algorithms for the proposed postponement schemes and show the superior performance of implementing such schemes over the traditional cellular operation.