电流互感器饱和对继电保护越级跳闸的影响

介绍了包钢中压电力系统中引起电流继电器误动和拒动的原因;分析电流互感器饱和对电磁式电流继电器、晶体管电流继电器动作行为的影响;论述了几种防止和抗御电流互感器饱和的方法及对策,如在较高一级的电压等级的供电侧采取分裂运行的方式以减小短路电流等.     

短路电流计算在电力系统事故分析中的应用

通过对武钢电网发生的三起典型跳闸事故的简要介绍,论证短路电流的计算在电力系统事故原因分析中的重要作用,利用故障时短路电流的大小来推断故障点位置,从而缩短故障查找的时间。短路电流计算为电力系统事故原因分析和继电保护装置动作评价提供了有力的数据支撑。     

提高矿井供电可靠性的措施

最近，山东省煤炭科学研究所和山东科技大学通过对矿区供电系统在过流保护和高压漏电保护方面存在的问题进行分析，提出解决方法：（1）采取相应措施提高过流保护的可靠性。对于设备起动电流大、线路短路电流小引起的问题，可以根据系统的运行情况采取以下方法解决，①人为增大短路电流，明显区别起动电流与短路电流，保证发生短路故障时保护装置可靠地动作，起动时电动机顺利地起动。     

一起10 kV电缆短路故障计算与分析

介绍了一起典型的10 kV电缆中间头短路故障现象,从故障录波信息中对故障的发生经过进行了详细的分析。计算了短路电流,分析了继电保护装置的动作可靠性,针对事故发生原因给出了建议和措施。     

限流电抗器与可恢复式大容量高速开关装置的组合应用

针对串联限流电抗器在运行中存在耗能及影响系统稳定等问题,将电抗器与大容量高速开关组合成新的装置,该装置能在系统短路后7～15 ms内切断电流,同时还具有开断能力强、使用寿命长、动作可靠性高、动作分散度小、合闸无反弹等特点。     

66kV直供电矿热炉用真空断路器的故障分析及处理

高压真空断路器是利用"真空"(气压为0.01~0.000001 Pa)灭弧的一种断路器,是电力线路中重要的一次控制设备,不仅能通断正常负荷电流,而且还能接通和承受一定时间的短路电流,并能在保护装置作用下自动跳闸,切除短路故障,具有体积小、重量轻、动作快、安全可靠等优点,适用于频繁操作的场所。     

大容量开关柜参数选定

在220t/h锅炉发电系统中,对于接入电网系统中的发电机,一旦出现短路点,若不能及时将其切除,短路电流对电网冲击直接引起越级跳闸,因此就需引入大容量开关柜,以保证系统的稳定。对于大容量开关柜来说,动作的参数选定是至关重要的,本文引入了具体的计算,以确定出合理的参数范围。     

主变低压侧加装限流电抗器的方案研究

在主变低压侧母线短路电流过大时,可采用高阻抗变压器或主变低压侧加装限流电抗器的方案来限制短路电流。限流电抗器的选择需考虑限制短路电流的效果、母线电压损失及技术经济性等多个方面的影响。结合具体工程实例,对主变低压侧加装限流电抗器的方案及需要注意的问题进行了研究。     

电流互感器的特性对继电保护装置的影响

分析在电路三相短路情况下，电流互感器的特性对继电保护装置的影响，提出了减少影响的措施。     

电流互感器的特性对继电保护装置的影响

分析在电路三相短路情况下，电流互感器的特性对继电保护装置的影响，提出了减少影响的措施。     

Effect of a Nonstationary Electric Current on the Oxide Melt–Gas Phase System

The influence of a nonstationary electric current on an oxide melt is studied. A nonstationary energy action is found to change the microstructure of a liquid system and to promote unlikely chemical reactions between an oxide melt and gas components. The division of the gas-phase components into oxidizing and reducing gases becomes rather conventional. It is found that stable application of an electric current can bring the system to a quasi-equilibrium state, which can retard the development of a chemical reaction, and the chemical reaction during the process can generate an electric current.     

高频开关电源在变电所的应用

对济钢第一炼铁厂变电所操作电源进行改造 ,应用高频开关电源替代原装设补偿电容器的硅整流电源 ,实现了操作电源不间断供电和二次回路可靠动作 ,保证了变配电系统的安全稳定运行     

Group pressure and action against a person.

A distinction is made between action conformity and signal conformity; the former refers to group-induced behavior that has more than an informational impact on the environment. A study of action conformity is described in which the effects of group pressure are measured by comparing the amount of electric shock administered by a naive S to a person, under experimental and control conditions. In the experimental condition the S performs in the midst of 2 confederates who call for increasingly more powerful shocks against a victim. The naive S has control over the level of shock and can hold down the punishment or yield to group influence. In the course of 30 critical trials the mean shock levels rise in response to the confederates' pressure. The structure of the experimental situation is examined by a comparison with Asch's study of verbal compliance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of electrodynamic phenomena in arc furnaces on the meniscus formation in a liquid metal

The main laws of the electrodynamic action of an electric arc on the surface of the liquid metal bath in electric arc furnaces of various types are considered.     

Effect of ATP on radiation damage to DNA caused by prolonged irradiation

The influence of bradykinin and kallikrein on the action of norepinephrine, epinephrine, isoprenaline, phentolamine, propranolol, aminophylline and theophylline on blood pressure was studied. The kinins potentiated the hypertensive action of norepinephrine and epinephrine, weakened the hypotensive action of isoprenaline, potentiated the hypotensive action of propranolol, and had no effect on the action of phentolamine, aminophylline and theophylline.     

Innovation approaches to controlling the electric regimes of electric arc furnaces

The processes of current passage in an ac electric arc furnace (EAF) are subjected to industrial experiments and mathematical simulation. It is shown that, when a charge is melted, arcs between charge fragments exist in series with main arc discharges, and these arcs influence the stability of the main arc discharges. The measurement of instantaneous currents and voltages allowed us to perform a real-time calculation of the electrical characteristics of a three-phase circuit and to determine the θ parameter, which characterizes the nonlinearity of the circuit segment between electrodes. Based on these studies, we created an advanced system for controlling the electric regime of EAF.     

外加电场对铝酸钠溶液自发分解的影响

研究了电场对铝酸钠溶液自发分解的强化作用,借助扫描电镜和X-射线衍射仪分析了分解产物的形貌和物相组成。结果表明:在电场作用下,铝酸钠溶液的自发分解率显著提高;电场有效促进了初生晶核的形成,缩短了成核诱导期,而且不会改变铝酸钠溶液分解产物的物相,分解产物仍为三水铝石。     

电场时效对铝锂合金性能和断裂特征的影响

研究了电场时效处理对 14 2 0合金板材性能的影响 ,探讨了其作用机理。研究发现 ,电场时效可在一定程度上提高合金的延伸率 ,且试样作负极时效果更明显 ;但电场对合金的强度几乎没有影响 ;电场时效还改变了合金的断裂方式 ,减小了沿晶分层断裂比例 ,增加了穿晶断裂比例和微区塑性变形。电场是通过对空位的作用来影响合金的析出相变、PFZ的形成和合金元素的晶界偏析 ,从而改善合金的性能     

电场对铝酸钠溶液晶种分解过程的影响

研究了电场对铝酸钠溶液晶种分解过程的影响,考察了不同温度和苛性碱质量浓度条件下电场对铝酸钠溶液非晶种分解过程和晶种分解过程的影响,并用扫描电镜、X-射线衍射仪分析了分解产物的形貌和物相组成。试验结果表明:铝酸钠溶液的分解率在电场作用下显著提高;电场能促成大量初生晶核的形成,以及一些大颗粒氢氧化铝的附聚,缩短了成核诱导期;电场不会改变铝酸钠溶液分解产物的物相。     

稀土氯化物熔盐电解原料对电流效率的影响

在氯化物熔盐电解中,电流效率的影响因素很多,主要叙述了原料中的杂质对电流效率的影响及影响原理,并针对氯化物电解原料中的杂质,总结了提高电流效率的方法.