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介绍了并联电容器使用不当引起的5种故障案例:并联电容器投入不当引起的供电线路事故、并联电容器的工作环境温度过高引起的温控设备频繁跳闸故障、代换的并联电容器与原电容器电压规格不相符引起的系统功率因数过低故障、电容器配套接触器不合格引起的过热故障、电容器安装不规范引起的电容器法兰渗油故障。分析了这些故障产生的原因,介绍了故障处理的方法和步骤,以及避免发生同类故障的防患措施。 相似文献
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直流电源系统接地引起保护误动作的分析及对策 总被引:1,自引:0,他引:1
分析了直流电源系统接地引起保护误动作的情况,其中在特定条件下,直流电源系统一点接地也会引起保护误动作,这要引起充分的关注。阐述了直流电源系统装设绝缘监察装置的必要性,分析了按直流电桥原理构成的绝缘监察装置的工作原理、主要参数以及不足之处;阐述了该装置目前运行的共同特点,研究了直流电源系统两点接地的后果,重点分析了一点接地电容放电引起保护出口继电器误动的情况,并给出了防范措施。 相似文献
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断路器在热备用、控制回路断线在恢复时引起的重合闸误动使断路器合闸;弹簧未储能引起的重合闸多次动作重合在永久故障上;在就地分闸时,断路器重新合上;在合闸时,引起事故音响等。有的问题会引起事故或事故扩大,及运行人员误判断。通过分析和试验,在断路器控制回路逻辑上进行了简单的改造,解决了出现的问题,取得了较好的效果。 相似文献
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失效VRLA蓄电池容量恢复的研究 总被引:4,自引:1,他引:3
研究了失水引起开路电压极低或热失控引起失效的VRLA蓄电池的容量恢复的可行性 ,并对硫化引起热失控的机理进行了研究。通过对VRLA蓄电池的失效原因进行分析 ,提出了容量恢复的可能性 ;采用先对开路电压极低的蓄电池加适量水和少量电解液 ,或对热失控蓄电池加适量水 ,再反复进行分级恒流充电和大电流放电循环的方法 ,进行了容量恢复的实验。结果表明 ,该方法对于失水引起开路电压极低或热失控引起失效的VRLA蓄电池 ,只要未发生短路、正极板栅腐蚀和活性物质脱落等不可逆故障 ,其容量恢复率可达 90 %以上。 相似文献
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对某变电站不接地系统中1条馈出线因断线故障引起的铁磁谐振进行了分析,并对各种可能的断线故障所引起的分频、基频、高频谐振分别进行了验算。总结了不接地系统的断线谐振的规律,并提出有关预防措施和对策。 相似文献
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铁磁材料的磁致伸缩效应是引起电机振动噪声的主要原因之一。为了计算磁致伸缩引起的径向磁通电机定子铁心振动,基于压磁方程和牛顿第二定律分别建立磁致伸缩引起的电机定子铁心振动精确解析模型。利用解析模型确定了各物理量之间的关系。得出磁致伸缩引起的电机定子铁心振动与磁致伸缩系数成正比,定子铁心轭部和齿部的振动位移分别与轭部圆环半径、齿高近似呈线性关系,弹性模量对磁致伸缩引起的电机定子铁心振动影响很小。利用有限元法和实验测试验证了磁致伸缩引起的电机定子铁心振动精确解析模型的准确性。最后,利用定子铁心振动实验和有限元法对解析模型进行验证,通过解析计算值、有限元计算值与实验测试值的对比,验证了解析模型的准确性。 相似文献
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通过一起200 MW发电机组有功功率波动引起的不安全事件,依据数据波形,从无功功率、电网频率、调节级压力、励磁调节系统、一次调频等因素对发电机组有功功率的影响分析入手,得出了引起发电机组有功功率波动的影响因素。并通过进相运行时有功波动引起的跳机实例,提出了应对防范措施,进一步对单机运行情况做出了合理的运行方式选择和机组负荷指标优化,避免再次发生类似现象。 相似文献
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In reported incidents, different types of voltage instability have occurred and each has presented in a quite distinct manner. To better acquaint power engineers with the different types, two incidents are described as each commenced with a type of system voltage instability and culminated with radial voltage instability. In neither of these two incidents were operators fully aware of the situation. The analysis of the incidents provided in this paper can give important operational insights. In particular it shows the value of timely load shedding and the need to allow a 20% margin from the radial voltage stability limit 相似文献
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暂态电能质量问题会对用户设备的正常工作产生影响,有必要从用户角度来理解引起的供电可靠性问题。介绍了国内外传统的可靠性指标和量化暂态电能质量事件的SARFI指标,提出了将暂态电能质量事件,特别是电压暂降和短时中断的影响纳入可靠性指标和评估中值得展开研究的几个方向。 相似文献
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为综合评价电网运行规划阶段分负荷方案的优劣,构造了一套涵盖电力系统经济性、安全性、可靠性和电力安全事故风险的电网运行规划分负荷方案评价指标体系。该指标体系首次将电力安全事故风险纳入评价考虑,涵盖范围广,能综合反映电网运行规划分负荷的实际需求。在获取各分负荷方案评价指标值的前提下,利用TOPSIS(Technique for Order Preference by Similarity to Ideal Solution)方法求解分负荷方案优化这一多目标决策问题,简单实用、可操作性强。实际系统仿真算例验证了 相似文献
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Chin Long Mak Fan H.S.L. 《Intelligent Transportation Systems, IEEE Transactions on》2007,8(3):480-490
Most automated expressway incident detection algorithms were successfully developed using loop-based traffic occupancy from their local conditions. However, the performance of these algorithms was not satisfactory on sites that have installed a video-based detector system. Due to different traffic detector technologies and varying driving behaviors from one region to another, it is of interest to develop an algorithm that uses video-based data. This paper used a total of 160 incidents collected along the 15-km central expressway (CTE) in Singapore to develop two new dual-station algorithms: the combined detector evaluation (CODE) and the flow-based CODE algorithms. On average, the flow-based CODE algorithm yielded better performance than the CODE in terms of average reduced false alarms of about 16%. Measures were also taken to ensure that the algorithms were properly developed and assessed. It was found that the CODE algorithm can detect, on average, up to 57% of the incidents faster than those of existing detection methods on CTE. 相似文献
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考虑到传统开关函数模型只对逆变电路的控制变迁进行分析而无法描述电路的条件变迁,容易丢失电路在条件变迁过程中所表现出的故障信息,从而影响故障诊断的实时性和准确性。电力电子电路是典型的混杂系统,文章建立了一种新型容错逆变器的混杂系统模型,在此基础上提出了故障事件辨识向量的概念,并将其应用于逆变器故障的分析,仅通过故障事件辨识向量对逆变电路变迁过程中的故障事件进行辨识来完成故障诊断,对于电路变迁过程中的正常事件辨识不予考虑,减少了控制系统的数据处理量,提高了故障诊断的实时性和可靠性,实验验证了所提方法的可行性和有效性。 相似文献
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In recent years, Hydro-Quebec has undertaken a major program to upgrade the reliability of its transmission system. Much effort has focused on increasing the system's ability to withstand extreme contingencies, usually caused by multiple incidents or the successive tripping of transmission lines. In order to counteract such events on its system, Hydro-Quebec has adopted a number of special defensive measures, globally called the “defence plan against extreme contingencies”. The goal of this plan, which will be fully operational by 1998, is to detect and confine incidents that exceed the system's strength. This paper summarizes Hydro-Quebec's current orientation for safeguarding its transmission system after extreme contingencies and describes the various automatic measures adopted and, in particular, the RPTC system, one of the main components of the defence plan. The RPTC system will detect multiple line losses directly from fifteen 735 kV substations, include four generation rejection sites and a centralized remote load shedding system 相似文献
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对目前系统发生多起二次设备损坏及误动调查研究,发现各(厂)站二次系统等电位接地点设计较混乱情况,根据相关要求,结合电网继电保护二次系统接地的需求,对地点设计分类进行研究,并给出具体措施。 相似文献
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U. Di Caprio 《International Journal of Electrical Power & Energy Systems》1984,6(2):112-126
The main trends of research underway at ENEL in the field of power system analysis and control are described. Topics covered include stability analysis, dynamic equivalents, reconstruction of real incidents, disturbance detection, emergency control, centralized system control, load forecasting, reactive and active power dispatching, scheduling of hydroresources, optimization techniques and power station control. 相似文献