The behavior of water in XLPE and EPR cables and its influence onthe electric characteristics of insulation

This paper presents the latest results of continuous investigations of cable insulations degradation of crosslinked polyethylene (XPLE) and ethylene-propylene with rubber based formulation (EPR) when subjected to electric stress and heating in the presence of water or water vapour. The paper deals with water absorption and diffusion in two kinds of crosslinked polyethylene insulation-dry-cured and steam-cured, and steam-cured EPR insulation. The aim of this investigation is to present the results of the influence of changing of water or water vapour pressure in the conductors of XLPE and EPR cables in different service conditions on the electric characteristics of XLPE and EPR insulations-breakdown voltage (AC BDV), dissipation factor (tan δ) and rata of partial discharge (RPD). In this paper, RPD is defined as, the maximum electrical field when the beginning partial discharge in the cable insulation and partial discharge were measured in accordance with the IEC standard. This paper also shows the relation between AC BDV and water content, and AC BDV and tan δ in XLPE and EPR insulations. In this testing the tap water was put in the cable conductors and the ends were properly closed by terminal boxes. The results indicate that the combined effects of water or water vapour, pressure, moisture, electric field and temperature will greatly accelerate deterioration of XLPE and EPR insulations     

大型汽轮发电机并联环和主引线水路故障分析和预防

大型水氢氢汽轮发电机并联环过热引发的电气事故多次发生，其根源在于水路故障和缺少有效的监测措施。分析和试验表明并联环水路设计是合理的，安装错误和运行不当是引起故障的主要原因，分析引起气堵的各种因素和发展为汽堵的机理，提出预防和改进措施，类似事故是完全可以避免的。     

SPE水电解高性Pd/C催化剂及最佳使用条件的研究

为了寻找最佳的固体聚合物电解质(SPE)水电解阴极催化剂,采用最简单的制备方法浸渍-还原法合成Pd基催化剂。通过对催化剂进行循环伏安测试、交流阻抗测试、线性极化测试和X射线衍射(XRD)、透射电子显微镜法(TEM)表征,结果发现对载体C进行酸化预处理,反应温度为90℃,p H=10时,可以获得高性能的SPE水电解阴极Pd/C催化剂。     

Improvement of microwave power from a virtual cathode oscillator and its repetitive operation using a metal mesh anode

A virtual cathode oscillator with a stainless‐steel mesh anode of various transparencies and wire diameters was studied experimentally for the enhancement of microwave power and its repetitive operations. The maximum microwave power observed was about 20 MW at 12 GHz for a diode voltage of 250 kV and an electron beam current of 39 kA using an anode mesh with wire diameter of 0.22 mm and a transparency of 67%. The microwave emission was enhanced by decreasing the mean angle of beam scattering when a mesh of smaller wire diameters was used in the anode. The increased transparency of the fine mesh also contributed to the enhancement of the microwave emission. Use of the mesh anode afforded the operation in several repetitive shots. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 146(2): 1–10, 2004; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10259     

家庭厨房热水使用习惯的监测装置与方法

本文介绍一种用于家庭厨房热水使用习惯监测的测试装置及其测试方法。其在用户长期热水使用过程中获取用户使用习惯,例如三口之家一次做饭做菜使用水的频次,热水使用的时长、间隔等等。其主要用于帮助热水终端(如热水器、混水阀)厂商提升产品的用户体验。     

Research of sorption processes using chemical water purification sludge for nitrogen and sulfur oxides contained in smoke gases emitted from a thermal power station

The possibility of the use of chemical water purification sludge of the Kazan Thermal Power Plant-1 as a sorbent for treatment of smoke gases is considered. The sorption capacity was studied, the sorption isotherm was obtained, and an adsorber with a fixed layer of sludge and acting periodically was analyzed.     

Preparation of lithium-ion polymer battery using LiNi1/3Co1/3Mn1/3O2 as a cathode material and its electrochemical properties

In this work, LiNi_1/3Mn_1/3Co_1/3O₂ powders were synthesized from co-precipitated spherical metal hydroxide. In the voltage range of 2.8–4.2, 2.8–4.4, and 2.8–4.6 V, the discharge capacities of LiNi_1/3Mn_1/3Co_1/3O₂ electrode were 163, 177, and 193 mAh⋅g⁻¹, respectively. A gel polymer electrolyte (GPE) was also prepared using polyoxyalkylene glycol acrylate (POAGA) as a macromonomer. LiNi_1/3Mn_1/3Co_1/3O₂/GPE/graphite cells were prepared and their electrochemical properties were evaluated at various current densities and temperatures. The ionic conductivity of the GPE was more than 6.2 × 10⁻³ S⋅cm⁻¹ at room temperature. POAGA-based cells were showed good electrochemical performances such as rate capability, low-temperature performance, and cycleability.     

Experience gained from using water and steam for bringing the operation of aircraft- and marine-derivative gas-turbine engines in compliance with environmental standards

Practical experience gained from using water and steam admission into the combustion chambers of aircraft- and marine-derivative gas turbines for bringing their operation in compliance with the requirements of environmental standards is described. The design and schematic modifications of combustion chambers and fuel system through which this goal is achieved are considered. The results obtained from industrial and rig tests of combustion chambers fitted with water or steam admission systems are presented.     

Safety considerations when placing a person with tools in an air gap to change porcelain and glass insulators on transmission systems of 345 kV and above, using ladder and aerial lift methods

This paper provides general considerations for determining working clearances required to carry out live line barehand insulator change out work on energized power lines operating at 345 kV and above. It is intended to focus on a limited number of procedures and only addresses one common structure configuration. This paper is intended to be used in conjunction with IEEE 516 Guide for Maintenance Methods on Energized Power Lines.     

Compensation for neutral point potential in a three‐level inverter using motor currents of a permanent magnet synchronous motor and its characteristics

A three‐level inverter has several advantages of large capacity, large voltage, and low current waveform distortion. However, there is an important problem of neutral point potential variation in three‐level inverters. The variation causes an unbalance in the dc link voltage levels and current waveform distortion. In this paper, we propose a new method to control the neutral point potential. First, the neutral point potential variation in a three‐level inverter for permanent magnet synchronous motor drive is analyzed by state variable method and is calculated on the basis of the analytic results. Second, using the estimated value, proposed compensation for the variation can be done. Third, analytic and experimental results of the proposed method are compared with the results of feedforward compensation by simply adjusting the vector output intervals. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 139(4): 56–63, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10033     

基于TCP/IP协议激光测距仪数据读取及在Labview的实现

介绍了基于TCP/IP协议的激光测距仪的数据读取方法,该方法相对传统的串口数据传输有很多优点。同时介绍了Labview开发平台,并用该平台对基于TCP/IP协议的激光测距仪的数据读取进行了实现,就实时性数据读取和数据漂移问题对程序进行了改进,结果表明:该方法有效的提高了编程效率,节约了开发时间。     

Experience gained in a number of countries from using thermal power stations equipped with diesel and gas engines

Large-capacity thermal power stations and customer’s cogeneration stations equipped with diesel and gas engines, and their technical-economic and cost indicators are considered.     

Results from investigating the erosion resistance of materials in high-velocity flows of water and a two-phase mixture in the flow path of injectors

Results are presented from an experimental investigation into the erosion resistance of materials in high-velocity flows of water and a two-phase medium with steam generation and condensation.     

A comparative analysis of the economic effect from using cogeneration gas-turbine units and combined-cycle plants in a power system

The net cost of heat production at cogeneration stations equipped with gas turbine units, steam turbine units, and combined-cycle plants is analyzed by way of comparison. It is shown that the minimal net cost will be achieved in the case of using certain types of power installations depending on the network tariff for electric energy.     

Experience gained from using a computer program implementing the 3D zone-wise method for calculating heat transfer in the furnace chambers of the coal-fired boilers of 350- and 575-MW power units

We describe the experience gained from more than 10 years of using the computer program imple-menting the 3D zone-wise method for calculating heat transfer in the furnace chambers of 350- and 575-MW power units installed at thermal power stations of Israel.