锂离子电池建模现状研究综述

随着新能源装机规模的逐年递增,电网对储能系统的辅助服务需求日益加重,合理地大规模集成储能电池单元,并通过电池管理系统进行有序控制是未来储能系统应用发展的关键。但由于目前对储能电源模型的研究远远滞后于实际工程需求,因此建立精准的电池模型是电池管理的迫切需要。本文在对比储能现有模型分类的基础上,通过对相关电池建模资料的梳理,分析了电化学模型、黑箱模型与等效电路模型的优缺点与应用场景,重点比对了单体电池的Rint、Thevenin、PNGV等多种等效电路建模方法,并阐述了不同单体模型在多种应用场景下的优势和局限性;同时对电池模组串并联顺序以及电池单体的不一致性影响进行了讨论,可为电池模组化和大规模储能系统应用的性能评估与发展提供参考。     

小电流接地系统故障定位方法综述

介绍了国内外电力系统中性点接地方式的现状和小电流接地系统发生单相故障的特点,详细阐述了小电流接地系统故障定位的方法,深入分析了定位原理,比较了各种方法的优缺点。指出了当前小电流接地故障定位存在的主要问题,并给出了小电流接地故障定位研究的几点建议。     

Optical current transducers for power systems: a review

The technology of the optical measurement of current is revived. Several fundamentally different approaches are described. Implementations from a number of manufacturers are examined so as to highlight the similarities and the differences. Experience with optical current transducers is reported. The question of interfacing to an optical current transducer is discussed. The special problems posed by calibration of this kind of instrument are reviewed     

A magneto-optic current transducer

A current measurement technique using the magneto-optic or Faraday effect, has been developed, tested, and demonstrated. The device developed is a magneto-optic current transducer (MOCT). It uses the rotation of the plane of polarization by a magnetic field exhibited in certain glasses (Faraday effect). Test data obtained in an extensive field evaluation of the MOCT were compared with the design qualification data gathered during the development phase of this project. The analysis indicates that operation of the MOCT-based metering system under field conditions compares favorably with performance predicted during design qualification     

基于电流突变量的自适应过电流保护新原理

针对线路外部故障切除时负荷自启动对配电网过流保护的影响,提出了一种基于电流突变量的自适应过电流保护新原理。利用线路在配电网内部故障与故障切除过程中电流存在的明显差异特征,实现对负荷自启动过程的准确识别。当连续两次检测到电流突变量大于设定门限值并满足两个判据时,即判定负荷产生自启动过程。给出了一套过电流保护整定方法,可根据负荷变化做出动态调整,从而构建自适应过电流保护方案。仿真结果表明,基于电流突变量的自适应过电流保护新原理是有效和实用的。该原理不受负荷自启动与负荷变化的影响,可有效增大后备保护的保护范围,保证了保护的可靠性和灵敏度。     

抑制漏电流的非隔离电流型光伏并网逆变器

针对非隔离光伏发电并网系统的漏电流问题,提出了一种直流母线开关对称的非隔离电流型光伏并网逆变器.给出了逆变器主电路拓扑结构和开关组态,通过建立光伏电池寄生电容的共模等效电路模型,分析了漏电流的产生和抑制机理.根据开关组态和抑制机理,设计了相应的单极性双载波调制策略和准PR控制策略.仿真和实验结果表明,所提变流器具有良好...     

一种基于虚拟电流制动量的电流差动保护

为了减小负荷电流增加制动量对电流差动保护灵敏度的影响,提出了一种基于虚拟电流制动量的电流差动保护。首先比较线路两侧电流大小,利用两侧电流幅值比与相位关系构造虚拟电流,虚拟电流可以根据线路两侧电流幅值关系自适应调整制动量大小。与利用线路两侧电流相位差的制动量相比:区内故障时,虚拟电流制动量小于电流相位差制动量,提高了电流差动保护灵敏度;区外故障时,虚拟电流制动量等于电流相位差制动量,电流差动保护的可靠性不降低。同时分析了弱馈线路、串补线路电流反相两种情况下虚拟制动电流的适应性。利用RTDS建立仿真模型验证保护的动作性能。仿真结果表明,虚拟电流制动量可以有效提高电流差动保护的灵敏度和可靠性,同时具有良好的适应性。     

A review of studies on the electric field and the current induced in a human body exposed to electromagnetic fields

How high an electric field or current is induced inside a human body when exposed to an electromagnetic field has recently attracted much attention. The background for this is twofold; concern about the possible health effects of electromagnetic fields (usually called ‘EMF issues’), and their positive application to medical treatment or new research subjects. This paper reviews various aspects related to this topic in terms of the following items: basic formulas for field calculation, effect of electromagnetic fields, calculation methods, an Investigation Committee in the IEEJ, and future research subjects. © 2006 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

一种基于差流波形特征的励磁涌流识别方法

提出了一种基于差动电流波形特征的励磁涌流和故障电流识别方法。励磁涌流的共同特征是受铁芯饱和程度的影响,差动电流是流过励磁绕组的实际电流,因而这一特征表现得更加明显。定义波形系数为磁通未饱和部分对应的电流在整个周期中所占比例,当系数大于阈值时判定为励磁涌流。为防止误动,当系数小于阈值时,引入"是否完全偏向时间轴一侧"作为辅助判据,使得该方法更加可靠。最后进行空载合闸仿真试验,证明了该方法能识别各种情况下的励磁涌流,性能优于二次谐波制动和间断角判据。     

中国胶体蓄电池的现状及前景

概述了中国胶体电解质铅酸蓄电池的技术现状及发展趋势,作者强调胶体的质量及灌装技术虽对电池的质量有重大影响,但它们在很大程度上要受电池的设计、结构、运行条件及充放电制度的制约。至于电动自行车用的胶体阀控电池,根据实际应用验证,其隔板宜用PVC SiO2型的,而不是AGM。     

一种混合式光学电流互感器的设计

介绍了一种混合式光学电流互感器,它包含两个传感输出通道:传统采样电流传感通道和块状光学玻璃传感通道。利用采样电流传感器的高精度稳态输出对光学玻璃传感头进行跟踪系数校正,有效地提高了整个混合式光学电流互感器的稳态精度和暂态精度。本设计使得光学电流互感器的频带宽、无磁饱和等一系列优点得到充分发挥,同时具有的双输出通道也是对电力系统保护的一种冗余设计,为目前光学电流互感器的实用化提供了一种全新的思路。     

一种混合式光学电流互感器的设计

介绍了一种混合式光学电流互感器,它包含两个传感输出通道:传统采样电流传感通道和块状光学玻璃传感通道.利用采样电流传感器的高精度稳态输出对光学玻璃传感头进行跟踪系数校正,有效地提高了整个混合式光学电流互感器的稳态精度和暂态精度.本设计使得光学电流互感器的频带宽、无磁饱和等一系列优点得到充分发挥,同时具有的双输出通道也是对电力系统保护的一种冗余设计,为目前光学电流互感器的实用化提供了一种全新的思路.     

光纤差动保护补偿电容电流的一种策略

针对输电线路分布电容对差动保护的影响,提出了一种克服电容电流对其影响的保护方案.线路正常运行时,将相电流差动保护的定值整定为线路电容电流的2倍以上,零负序差动保护的定值整定为线路电容电流的1.5倍以上,可靠躲过线路正常运行时的电容电流.在线路空充时,将各差动保护的定值提高两倍同时增加一定的时延,可靠躲过暂态电容电流对各差动保护的影响.     

光纤差动保护补偿电容电流的一种策略

针对输电线路分布电容对差动保护的影响,提出了一种克服电容电流对其影响的保护方案。线路正常运行时,将相电流差动保护的定值整定为线路电容电流的2倍以上,零负序差动保护的定值整定为线路电容电流的1.5倍以上,可靠躲过线路正常运行时的电容电流。在线路空充时,将各差动保护的定值提高两倍同时增加一定的时延,可靠躲过暂态电容电流对各差动保护的影响。     

A modified dual current mode control method with an adaptive current bandwidth

In this paper, a new adaptive dual current mode control method (ADCMC) is presented, being a result of the modification of existing dual current mode control (DCMC) by introducing an adaptive current bandwidth. The ADCMC offers several important advantages over DCMC, such as no peak‐to‐average error in the inductor current, better transient response of current loop, and improved line regulation. A detailed analysis of the proposed ADCMC is performed for three types of DC–DC power electronics converters: buck, boost, and non‐inverting buck–boost converter. The performances of the ADCMC are tested with simulations and experiments. The obtained results confirm the analysis and validity of the proposed ADCMC method. Copyright © 2015 John Wiley & Sons, Ltd.     

A review of decentralized and distributed control approaches for islanded microgrids: Novel designs,current trends,and emerging challenges

Distributed energy resources (DER) on the demand side have been fast growing, which could boost energy resilience by uninterruptedly supplying the commercial and residential sectors in the form of islanded microgrids when the utility electricity grid is out of service. Nevertheless, simply applying the centralized hierarchical control strategies, traditionally used for utility electricity grids, onto the islanded microgrids would encounter several critical issues. For instance, the control goals in secondary and tertiary control could be activated tardily, the single-point fault could cause critical system failure, and the properties of dynamic plug and play would be hard to achieve. To this end, decentralized and distributed control approaches have been explored to cope with the issues. Specifically, compared to the centralized hierarchical control, decentralized and distributed control strategies can (i) respond to disturbances more promptly, enhancing the performance of islanded microgrids with limited resources; (ii) guarantee system stability especially when a fault occurs and certain DERs are disconnected from the network; and (iii) facilitate deeper penetration of DERs in the microgrid, owning to the low computational complexity and sparse communication network. In this article, the common approaches for decentralized and distributed control are reviewed, and the current design trends and critical technical challenges are discussed to offer a comprehensive understanding of decentralized and distributed controlled microgrids.     

一种新型的双极性脉冲电流源

在瞬变电磁探测领域中,发射电流波形的质量将会直接影响到地质体感应信号的检测。瞬变电磁法理论基于阶跃波电流源激励,为了探测浅层部地质信息,要求脉冲电流关断延时短、上升下降沿线性度高,探测系统动态性能好,但由于发射线圈呈感性,在大电感负载下实现理想的阶跃脉冲是非常困难的。研究改善发射电流脉冲波形前、后沿波形质量的电路拓扑、控制方法,并研究了电磁发射机整流方案。分析了电路的工作原理,讨论了电路参数优化计算,从负载电流上升、下降沿波形的线性度和稳压电容电压波动范围出发,给出了恒流电路中电感值和钳位电容值的最优值选取方法,并通过仿真实验,验证了理论分析的正确性。与已报道电路相比,该电路结构简单,上升、下降沿线性度好,动态性能好。     

一种序分量检测新方法

针对传统dq变换法在检测电网序分量时的不足,提出了一种新的序分量检测方法,该方法不仅适用于负载不对称系统,而且适用于电源电压不对称系统.在检测过程中,不需要采用锁相环(PLL)电路获得同步旋转角,有效消除了PLL延时带来的影响;也不需要进行三角函数计算,降低了算法的复杂度.仿真分析表明,本文所提出的方法在电源电压不对称和畸变时能有效检测出负载电流的正序、负序和畸变分量.