真空断路器的故障分析与处理

真空断路器的优越性不仅是无油化设备,而且还表现在它具有较长的电寿命、机械寿命、开断绝缘能力大、连续开断能力强、体积小、重量轻、可频繁操作、免除火灾、运行维护少等优点,很快被电力部门运行、检修和技术人员认可。本文对真空断路器在运行中经常出现的一些故障的原因进行了分析,同时给出了现场处理这些故障的方法。     

漏电保护器和小型断路器市场抽查结果与分析

漏电保护器和小型断路器是现代住宅和办公楼房普遍使用的两种开关电器,是安全用电的重要保护器件。由于它们不仅量大面广,且直接牵涉到消费者的人身和财产安全,因此对它们的安全性能和可靠性要求很高。对漏电保护器和小型断路器,国家分别制定了等效采     

如何合理选择10kV配电变压器的保护配置

10kV配电变压器的保护配置主要有跌落式熔断器、断路器、负荷开关加熔断器等。跌落式熔断器经济、操作方便,适用于小容量变压器;断路器技术性能好,但设备投资较高;负荷开关加熔断器可弥补负荷开关不能开断短路电流的缺点,又可满足实际运行的需要。本文对以上几种保护配置方式进行了比较分析,对如何合理选择进行了详细阐述。     

基于光电传感器的高压断路器电寿命在线监测系统

断路器的电寿命是衡量自身使用价值和使用期限的重要参数,而断路器电寿命在线监测系统能够为高压设备提供一些列的智能化检测服务,确保电力系统的安全可靠运行。本文提出一种基于光电传感器的高压断路器电寿命的在线监测系统,以光电传感器采集电流信号,以加权累计法计算电寿命,从而有效提升了系统的测量精准度,减少电力系统的检修次数,提高电力系统的安全性能。     

石油企业常用配电变压器保护配置方式的合理选择

10kV配电变压器是油田生产中的常用设备,其保护配置主要有断路器、负荷开关或负荷开关加熔断器等。负荷开关投资省,但不能开断短路电流,很少采用;断路器技术性能好,但设备投资较高,使用复杂,广泛应用不现实;负荷开关加熔断器组合的保护配置方式,既可避免采用操作复杂、价格昂贵的断路器,弥补负荷开关不能开断短路电流的缺点,又可满足实际运行的需要,该配置可作为配电变压器的保护方式,值得大力推广,为此,对10kV环网供电单元和终端用户10kV配电变压器采用断路器、负荷开关加熔断器组合的保护配置方式进行技术、经济比较,供配电网的设计和运行管理部门参考。     

矿用低压开关漏电保护问题分析

本文就目前南屯煤矿井下1低压智能馈电开关在发生漏电的时候进行具体的保护故障进行细致的分析，并对漏电保护的原因和机理作了详细的讨论，并在此基础和前提下提出了具体的解决措施和方案：可以在总开关的位置上同各国附加电容的方式来使得零序电流值增大，这样就能够实现对保护装置的综合采集并对其做进一步的分析，判断，也能够使得漏电之路的分开关能够依照在更为安全的环境中工作。可以采取必要的措施。在现场应用的结果中显示：经过改造之后的低压供电系统漏电保护运行是很正常的，总的开关漏电动作时间有显著的缩短。     

一种新型长寿命模块化弹簧操动机构真空断路器的研制

针对炼钢、投切电容器组电气零部件频繁操作造成断路器寿命缩短的问题,选用12kV-1250A-31.5kA弹簧操动机构真空断路器为研究对象,设计了一种新型精简、高效的传动方案,显著提高了刚分速度;对合闸弹簧、分闸弹簧及触头压力弹簧、缓冲器、传动环节、润滑等方面提出了长寿命设计理念,对关键薄弱环节进行仿真或疲劳寿命分析,全方位提升了产品机械寿命;采用模块化设计方法,将操动机构各功能模块集成设计在高强度铝合金箱体上,零件数量大幅降低,操动机构性能更加稳定,可靠性显著提升。在型式试验中,本文所述断路器在未检修的情况下一次性通过100次额定短路开断电流电寿命试验和6×10~4次机械寿命试验。该真空断路器已投入批量生产,具有实用推广价值。     

煤矿井下供电防越级跳闸控制系统

文章介绍了目前煤矿井下供电系统的现状,针对井下短路故障时越级跳闸和漏电故障时非选择性误跳闸的原因进行了详细分析,并给出了解决方法：对于短路故障时越级跳闸提出了一种将井下高压防爆开关的智能综合保护器的采样、处理、输出等冗余环节作为后备保护,加以直接的电流速断保护的改造方案;对于漏电故障时非选择性误跳闸提出了一种对总馈电开关和分支馈电开关分别采用不同保护方式的改造方案。实际运行表明,经改造后的BGP系列高压防爆开关有效地避免了因越级跳闸造成的大面积停电事故,减少了安全隐患,提高了生产效率,漏电保护的改造基本上满足了漏电故障准确跳闸的要求,提高了供电的安1开关机构配置不当。     

矿井低压电网选择性漏电保护 系统总体设计与实现

设计了一款以dsPIC30F4012为主控制器、PIC16F877A为从处理器的新型主从式选择性漏电保护系统。该系统在总开关处采用附加直流源检测原理检测是否发生漏电,在分支开关处使用零序功率方向检测原理判断发生漏电故障线路,给出了保护系统的硬件框图和软件流程图,并且采用速度更快的RS-485总线及光纤传输技术,实现了矿井低压电网漏电的保护的瞬动性。实验结果验证了该保护系统的优越性能。     

矿井井下电网越级跳闸的原因分析和探讨

文章介绍了目前矿井供电系统的现状．针对井下短路故障时越级跳闸和漏电故障时非选择性误跳闸的原因进行了详细分析,并给出了解决方法对于短路故障时越级跳闸提出了一种将井下高压防爆开关的智能综合保护器的采样、处理、输出等冗余环节作为后备保护,加以直接的电流速断保护的改造方褰对于漏电故障时非选择性误跳闸提出了一种对总馈电开关和分支馈电开关分别采用不同保护方式的改造方案。实际运行表明,经改造后的BGP系列高压防爆开关有效地避免了因越级跳闸造成的大面积停电事故,减少了安全隐患,提高了生产效率;漏电保护的改造基本上满足了漏电故障准确跳闸的要求,提高了供电的安全性和可靠性。     

Electrical characterization of small area devices for manufacturing

Uniformity of electrical performance is critical for thin film modules. The more uniformly that all areas of the module perform the better the overall efficiency will be. Total module performance tends towards the average of localized performance, skewed slightly lower by the width of localized performance distribution. Measurement of overall module efficiency does not give information about performance uniformity. Use of small area devices (SAD's) defined from the module allow standard electrical measurements including light and dark current-voltage (IV/JV) and quantum efficiency to be performed on a small scale. Data from these measurements allows mapping of electrical performance across the module. The structure of types of SAD's is discussed and some examples of efficiency data from JV measurements as used in the optimization of a thin film module manufacturing line are presented. Also a brief discussion of statistical analysis of the data is included.     

Electrical characteristics of nanoscale NAND silicon-oxide-nitride-oxide-silicon flash memory devices fabricated on SOI substrates

NAND silicon-oxide-nitride-oxide-silicon (SONOS) flash memory devices with double gates fabricated on silicon-on-insulator (SOI) substrates were proposed. The current-voltage characteristics related to the programming operation of the designed nanoscale NAND SONOS flash memory devices on a SOI substrate and on the conventional bulk-Si substrate were simulated and compared in order to investigate device characteristics of the scaled-down memory devices. The simulation results showed that the short channel effect and the subthreshod leakage current for the memory device with a large spacer length were lower than that of the memory device with a small spacer length due to increase of the effective channel length. The device performance of the memory device utilizing the SOI substrate exhibited a smaller subthreshold swing and a larger drain current level in comparison with those on the bulk-Si substrate. These improved electrical characteristices for the SOI devices could be explained by comparing the electric field distribution in a channel region for both devices.     

塔里木油田套管气密封检测技术现状及分析

为降低油田气井套管泄漏造成的事故风险,油田采用气密封检测技术来排查和检测完井套管的泄漏情况,保障套管的完整性,对塔里木油田气密封检测的原理、标准、现状、检测压力和检测时间进行了分析,并抽取部分检测报告对气密封检测检出套管不合格的原因进行了分析。结果表明:经卸扣、清洗、涂抹螺纹脂、排除外界干扰后再次检测,合格套管所占的比例较大。由于螺纹损坏或质量因素导致泄漏所占比例较小,认为现场操作、使用环境是造成气密封检测时套管不合格的主要因素。气密封检测技术能对接头工厂端气密封性提供技术保障,解决了油田工厂端缺少检测手段的问题。相比接头泄漏导致的严重后果,尽管下套管时间每根增加了近4 min,气密封检测仍是不可缺少的过程。泄漏率不会随着检测压力的增加而增加,与检测压力无直接关系,且检测压力为套管抗内压强度的60%时较为安全、可靠。     

Part-load characteristics of a new ammonia/lithium nitrate absorption chiller

A pre-industrial prototype of a new water-cooled ammonia/lithium nitrate absorption chiller was characterised at part-load operation mode. The chiller was built using brazed plate heat exchangers in all its components, including the absorber and the generator.A test campaign was carried out varying the thermal load in the chilled water circuit and keeping the hot and cooling water temperatures constant.Part-load curves of the thermal and electrical coefficients of performance were obtained, plotted and compared with data from the literature on small capacity absorption chillers with conventional working pairs, namely ammonia/water and water/lithium bromide. The experimental results showed that to achieve a higher electrical coefficient of performance at part-load operation, it was much more convenient to use an ON-OFF control than to modify the hot water temperature. Furthermore, using a simple ON-OFF control strategy, the behaviour of the new absorption chiller was more agile and responded more quickly.The part-load curve of the electrical coefficient of performance was obtained by adjusting the experimental data to the shape of the curve proposed in the standard prEN-14825:2011 for air-to-water chillers. The Cc coefficient was 0.7985 matching the value obtained dividing the remaining electrical consumption measured during the OFF half cycles by the total energy consumption generated.     

高可靠智能压力开关研发及应用

压力开关是火电机组保护系统中重要的一次信号元件,压力开关测量的准确性、可靠性及快速性直接决定了电厂保护系统能否正确、快速动作。针对机械式压力开关和压力变送器作为保护元件存在的不足,依据保护、调节、监视三分开控制系统设计原则,设计了微功耗、高可靠的两线制智能数显压力开关,并对智能压力开关进行可靠性设计和试验测试。测试结果表明,该压力开关有效地解决了传统压力开关存在的卡涩、偏移、不可监控和预测的问题,具有微功耗、高可靠、高精度和免校验等优点,为电厂保护系统的可靠运行提供了根本有效的保证。     

提高电厂厂用电系统安全性的方法

本文针对某厂厂用电系统面临的系统接线方式变化、安全性低等问题，对系统进行分析和研究。在现有设备的基础上，通过方案论证和对比，利用最小的投入，制定切实可行的改造方案，对现有厂用电系统进行技术改造。并对设备参数进行了校核确定，满足现场设备的运行需要。通过厂用电系统的改造，提高了全厂设备运行的安全系数，在各种运行方式变化的情况下，使厂用电系统的切换更加灵活，保证机组的安全运行，为电厂厂用电系统的运行提供了有益的探索和尝试。     

基于软PLC的电气测试系统设计

利用软PLC技术，设计一个电气测试系统，与传统的接触器控制测试系统相比，软PLC测试系统能有效降低成本，提高测试效率，增强系统性能。     

Fault diagnosis and refrigerant leak detection in vapour compression refrigeration systems

The environmental impact of refrigeration systems can be reduced by operation at higher efficiency and reduction of refrigerant leakage. Refrigerant loss contributes both directly and indirectly to global warming through inefficient system operation, increased power consumption and greenhouse gas emissions and higher maintenance costs. Existing sensor-based leak detection methods are limited by the inability to detect gradual leakage and the need for careful sensor location. There is a requirement for a real-time performance monitoring approach to leak detection and fault diagnosis which overcomes these disadvantages.This paper reports on the development of a fault diagnosis and refrigerant leak detection system based on artificial intelligence and real-time performance monitoring. The system has been used successfully to distinguish between faulty and fault free operation, steady-state and transient operation, leakage and over charge conditions. Work currently underway is aimed at testing additional fault conditions and establishing further rules to distinguish between these patterns.     

舰艇电气设备中簧片式触点开关冲击响应分析

簧片式触点开关广泛应用于舰艇的电气设备中。舰艇受到爆炸冲击时,簧片式触点开关易发生断路或簧片产生塑性变形,影响设备的可靠性,危害舰艇的安全。为了校核簧片式触点开关的抗冲击能力,首先对处于闭合状态的簧片式触点开关进行接触模态分析,然后对其施加多种典型冲击载荷并采用Bathe复合积分法开展计算,最后通过提取动、静触头之间的接触力来判断簧片式触点开关是否发生断路,同时观察簧片根部在冲击载荷下是否发生塑性变形。研究发现：动、静触头之间的接触力在冲击载荷作用时波动剧烈,而在自由振动时则呈现出明显的周期性,且振动频率接近一阶固有频率;在幅值相同的情况下,高频冲击载荷更容易诱发剧烈的接触颤振而断路,低频冲击载荷会使簧片根部的应力较大而塑性变形。讨论了负波延迟对冲击响应的影响,提出了改善簧片式触点开关抗冲击能力的措施。