发电机中性点配电变压器二次负载电阻的现场选取和校核

发电机中性点配电变压器二次负载阻值是按发电机及机端设备对地电容理论值设计的。其阻值是否合适．应在机组投产前实测参数以选取合理电阻抽头并进行校核。结合实例，提供了一套现场测试参数和配电变压器二次阻值抽头选取及校核的实用方法。     

Control System of Neutral Beam Injection on HT-7

Neutral Beam Injection control system (NBICS) is constructed to measure the plasma current, Magnet current, vacuum pressure, cryopump temperature, control water cooling, filament voltage, and power supply， etc. The NBICS, consisting mainly of a Programmable Logic Controller (PLC) subsystem, data acquisition and processing subsystem and cryopump and vacuum pressure monitoring subsystem, has successfully been used on a NBI device. In this article, the design of NBICS on HT-7 is discussed and each subsystem is described in particular.In addition, some experimental results are reported which are very important data for further research related to the HT-7 tokamak.     

新体系过氧化氢-中性红催化光度法测定亚硝酸根

研究了硫酸介质中,痕量亚硝酸根催化过氧化氢氧化中性红褪色反应及其动力学条件,建立了动力学光度法测定亚硝酸根的简便方法。lg(A_0/A)与亚硝酸根浓度在0～0.6μg/25mL范围内呈线形关系,方法的检出限为4.3×10~(-10)g/mL。     

Fault diagnosis in neutral point indirectly grounded system basedon information fusion

0　INTRODUCTIONInChina ,neutralpointindirectlygroundingsystemismostwidelyappliedinpowernetworks .Accordingtothenationalpowerdepartmentstatisticaboutelectricalnetworkfaults ,thephase to groundfaultsaccountforthegreatestpart.Sincewhenthisfaultoccurs ,three phaselinevoltageisstillsymmetric ,thefaultcurrentpassingthroughthegroundpointiscomparativelylow ,thusdoesnotinfluencethelastingpowersupply ,thereforethepro tectiverelaysdon’ttripimmediately .However,becausethevoltageofthenormalphasesisin…     

An LMI approach to guaranteed cost control for uncertain linear neutral delay systems

This paper considers the problem of guaranteed cost control for uncertain neutral delay systems with a quadratic cost function. The system under consideration is subject to norm‐bounded time‐varying parametric uncertainty appearing in all the matrices of the state‐space model. The problem we address is the design of a state feedback controller such that the closed‐loop system is not only stable but also guarantees an adequate level of performance for all admissible uncertainties. A sufficient condition for the existence of guaranteed cost controllers is given in terms of a linear matrix inequality (LMI). When this condition is feasible, the desired state feedback controller gain matrices can be obtained via convex optimization. An illustrative example is provided to demonstrate the effectiveness of the proposed approach. Copyright © 2002 John Wiley & Sons, Ltd.     

双频法在浮地交流电网绝缘故障定位中的应用

针对浮地交流电网，提出了用双频法对电网绝缘故障支路定位的方案，分析了对浮地电网注入低频信号后的漏电流特性，给出了从包含复杂频率成分的信号中提取注入频率电量的方法，注入频率的选择直接影响到双频法应用于电网绝缘故障支路定位的效果，在给定注入信号频率的选定原则基础上，根据实际情况，确定了注入信号频率的可选择范围，通过现场实际应用表明，该方案是可行的。     

广东110kV电网大面积停电问题的分析及解决方案

介绍了广东110kV电网大面积停电的情况，针对广东110kV系统接地方式，对110kV电网主变中性点放电间隙误动和保护动作配合时间失配的情况进行了详细的分析，提出了解决方案。     

对三相四线制供电系统中性点电位偏移的研究

介绍了三相四线制供电系统中线阻抗及三相负载变化对中性点电位偏移的影响，从理论上对偏移产生的原因作了分析，运用ORCAD／PSPICE9对三相四线制供电系统中性点电位偏移进行了仿真研究，并提出在实际应用中应注意的问题。     

配电系统的接地与漏电保护器的配置技术

论述了配电系统的接地方式及适用范围，文章在简述了RCD原理后，指出了正确使用RCD方法。     

一类非线性中立型微分方程的线性化振动

研究一类非线性中立型微分方程的线性化振动,应用勒贝格控制收敛定理得到非线性微分方程和相应的线性微分方程的比较结果.