浅议蓄电池选购、验收、使用和维护

本文从蓄电池的选购、验收、使用和维护的角度对提高蓄电池系统安全进行探讨。     

Conventional and recommended arc power and energy calculations and arc damage assessment

The costs associated with fires initiated by arcing faults depend on the extent of the damage. In some cases, costs have exceeded $100 000 000. The personal losses associated with a serious injury or fatality are incalculable. When an arcing fault occurs, qualified in-house personnel and/or professional consultants try to determine the factors involved in the fault's initiation. Investigators also serve as expert witnesses in any pending lawsuits related to the accident. In fact, the growing interest in accident investigation has led to the establishment of an IEEE workgroup in forensics. Even with sophisticated techniques like scanning electron microscopes used to provide magnified photographs of arc damage, only a limited amount of applicable technical information on arcing faults exists for reference. Much of the engineering reference information on calculating arc currents and assessing arc damage is 25-50 years old. Recent papers by the authors discussed calculating arc currents. This paper presents a method to determine the power released by a single-phase-to-ground arc and provides graphs for quick reference. Commonly used methods for calculating arc power and energy and quantifying damage are also discussed. The recommended and conventional methods are used to determine arc energy and to identify the damage threshold in a typical system and the results are compared.     

变频器与PLC的连接与配合使用

分析了变频器和PLC的配合使用的连接方法,提出了设计安装使用时的注意事项,给出了抗干扰的一些方法。     

Generator protection and CT-saturation problems and solutions

This paper presents a new generator relay design, stator differential function in particular, coping with extreme cases of current transformer (CT) saturation: both ac saturation under large currents and/or residual flux; and dc saturation under low currents but large and long-lasting dc components. The algorithm is a subcycle algorithm with fastest times reaching half a cycle including overall response of the relay hardware. Analysis of the response of a traditional differential function under CT saturation is included to provide setting guidelines for legacy relays.     

谐波及其危害与治理

从谐波的基本概念开始,阐述了谐波基本指标,谐波的危害、谐波的限制措施、谐波测量以及谐波治理等方面的知识并作了具体的分析。     

Present and Future Trends and Needs in Electric Power Quality Sensors and Instrumentation

Sensors and instrumentation systems form an important part of power quality assessment and preservation. In this paper, the present and future trends in power quality instrumentation are discussed and the present capabilities are identified (e.g., bandwidth, dynamic range, quantities measured). Innovative methods of instrumenting nonsinusoidal voltages and currents are described, including applications of the Global Positioning System (GPS), solid state sensors, sensors that involve light and video, advanced data compression techniques, and advanced state estimation. The cost-to-benefit ratio of sensor development is evaluated in the context of the deregulated electric utility business environment.     

SF6断路器巡视维护及常见故障原因分析与处理

SF6断路器是电力系统中的一个重要设备。在110kV及以上电压等级中,最常用的开断电器是SF6断路器。介绍了其特点,总结了正常巡视检查定期维护的方法,分析了产生故障的原因,并提出了在出现常见故障时采取的措施,为电网运行管理部门预防该类事故提供参考,从而确保安全优质持续供电。     

Tracing active and reactive power between generators and loadsusing real and imaginary currents

In a competitive environment, usage allocation questions must be answered clearly and unequivocally. To help answer such questions, this paper proposes a method for determining how much of the active and reactive power output of each generator is contributed by each load. This method takes as its starting point a solved power flow solution. All power injections are translated into real and imaginary currents to avoid the problems arising from the nonlinear coupling between active and reactive power flows caused by losses. The method then traces these currents to determine how much current each source supplies to each sink. These current contributions can then be translated into contributions to the active and reactive power output of the generators. It is also shown that the global contribution of a load can be decomposed into contributions from its active and reactive parts. This decomposition is reasonably accurate for the reactive power generation. To determine the contributions to active power generation, the previously-described method based on the active power flows is recommended     

德、法两国报刊、图书出版业考察有感

阐述了德、法两国报刊、图书出版业的发展趋势和概况,通过对欧洲书展和法、中文化交流活动的介绍,分析了德、法两国报刊、图书出版业的特点。结合宁夏的实际情况,借鉴国外先进经验,提出了本地区电力行业科技期刊的发展模式及思考。