2008年12月31日，由国内自主设计、自主制造、自主研发的世界首套容量最大的固定式直流融冰装置顺利通过试验并成功应用，标志着我国利用科技手段防灾减灾方面取得了又一重大突破。本套融冰装置的研制成功应用，将为提高电力系统抵御自然灾害的能力，确保电网在冰雪灾害下安全稳定运行提供更加有力的技术保障。
本套装置试验在湖南电网500kV复沙I线上成功完成，该线路导线规格为LGJ-4×300，长度为86公里。根据线路实际参数情况，试验时输出融冰电流4000安培，测点最大温升47℃，试验线路、金具、接头和直流融冰装置各设备运行正常，各项试验数据均达到设计要求，装置性能满足500kV线路融冰需求。
试验人员正进行温升监测
本套装置是世界首套成功应用于实际工程的固定式直流融冰装置，创造了容量最大、额定电流最大、融冰距离最长的世界记录，具备对四分裂500平方毫米截面导线融冰距离180公里能力。
固定式融冰装置SVC部分（整流阀室）
本套融冰装置设计容量120MW，额定输出电流6000A。同时，兼有静止无功补偿（SVC）功能，大大提高了装置的综合利用效率，装置作为SVC运行时，可为湖南电网最大提供120Mvar的动态无功补偿，将输电线路的暂态稳定极限提高50MW，有效提高湖南电网稳定性，大幅提高线路输送能力。
本项目的实施得到了国务院三峡建委的大力支持，由国家电网公司建设运行部全面负责组织实施，湖南省电力公司负责工程现场管理，湖南省电力勘测设计院设计，中国电力科学研究院负责总体集成并联合中国西电公司负责装置研发。相关单位成功攻克了装置在融冰模式下系统接入方式、阀组电气结构、融冰装置保护配置、绝缘配置等一系列关键技术难点，为项目如期投运奠定了基础。
国家电网公司在总结抗击低温雨雪特大自然灾害和恢复重建经验，坚持利用科技手段，全面实施科技防灾减灾项目，此前已于12月7日在湖南益阳复兴变电站试验成功了移动式直流融冰装置融冰，于12月16日在湖北咸宁变电站完成了移动直流融冰装置融冰试验，同时，12月31日凌晨江西梦山移动式融冰装置也已通过第一阶段试验，有关线路改造、加强工程也已陆续完成，为积极应对雨雪冰冻灾害做好了充分准备。
信息来源：国家电网公司 发布日期：2009-01-04
Friday, January 30, 2009
CT的带载能力是怎么计算的？
CT的带载能力是怎么计算的？
请问一个100/5电流互感器额定容量5VA可以带多大负载？
(摘自http://www.cibu.cn/botan/topic/2545.html ）
如果针对计量CT，从额定条件考虑，负载为0.2欧姆，即0.2*5*5=5VA。一般最大负载可以考虑到1.2倍，即0.24欧姆。
实际上，CT的设计有一定余量，通常2到3倍的额定负载不容易出现马上饱和的问题，但CT的工作误差会相应增大。
对于保护CT而言，一般允许较宽的过载能力，一般最大规定为30倍过载，误差限制在5%或10%以内，具体视应用条件和设计值为准。
针对CT的带载能力，不能简单从额定值出发考虑，大部分CT带电运行一段时间，其线性工作区域会发生变化，需要进行周期性测试或诊断性维护。从状态检修的角度，更多应考虑CT的传变电流和负载之间的调整关系（能力）。
更多技术或产品资料可以访问成都普莎拉科技有限公司网站（www.pusala.com)，互感器带电分析系统/带电CT带载能力测试。(http://pusala.com/transformeranalyzer.aspx)
请问一个100/5电流互感器额定容量5VA可以带多大负载？
(摘自http://www.cibu.cn/botan/topic/2545.html ）
如果针对计量CT，从额定条件考虑，负载为0.2欧姆，即0.2*5*5=5VA。一般最大负载可以考虑到1.2倍，即0.24欧姆。
实际上，CT的设计有一定余量，通常2到3倍的额定负载不容易出现马上饱和的问题，但CT的工作误差会相应增大。
对于保护CT而言，一般允许较宽的过载能力，一般最大规定为30倍过载，误差限制在5%或10%以内，具体视应用条件和设计值为准。
针对CT的带载能力，不能简单从额定值出发考虑，大部分CT带电运行一段时间，其线性工作区域会发生变化，需要进行周期性测试或诊断性维护。从状态检修的角度，更多应考虑CT的传变电流和负载之间的调整关系（能力）。
更多技术或产品资料可以访问成都普莎拉科技有限公司网站（www.pusala.com)，互感器带电分析系统/带电CT带载能力测试。(http://pusala.com/transformeranalyzer.aspx)
Thursday, January 29, 2009
ICE energy
Ice Energy is transforming energy system efficiency and grid reliability by enabling utilities to intelligently manage their load profile. Combining our revolutionary distributed energy storage technology with advanced, two-way, smart grid controls, our cost effective solutions make it possible for utilities to permanently level system load, increase off-peak load to better absorb the impact of intermittent renewable resources, and more effectively meet current and future renewable regulatory requirements.Until now, the industry has only imagined a technology that could completely reshape the load curve and optimize the grid, ensuring system reliability.
For more information, visit www.ice-energy.com/dtech10
For more information, visit www.ice-energy.com/dtech10
Saturday, January 17, 2009
Artesis Launches MCMSoC For Open Integration Of Condition Monitoring Technology
Taken from: www.engineeringmaintenance.infoArtesis, a leading supplier of intelligent predictive maintenance solutions, has launched the MCM System on a Card (SoC), a product for the OEM sector, bringing a highly efficient and easy to use tool suite that allows the fast and complete integration of Artesis’s advanced condition monitoring technology into a variety of industrial control and monitoring systems.Artesis provides a range of intelligent condition monitoring units to detect any changes in the condition of electric motor-driven equipment as well as generators and alternators and provides automated fault diagnosis. The Artesis intelligent monitor systems - Motor Condition Monitor (MCM) and Plant Condition Monitor (PCM) - both use an advanced technique known as model-based fault detection to allow fully automated setup and analysis. This allows the system to operate effectively with minimum user intervention, even when applied to equipment with varying speed and load conditions.The new MCMSoC enables OEM companies to integrate this unparalleled and highly advanced technology into a range of devices and systems and adding the MCM capabilities to control or monitoring systems. “The MCM predictive maintenance system is fast becoming an open, standards-based solution of choice for a wide range of applications in many industries,” said Andy Bates, director at Artesis. “Developing MCMSoC allows OEMs to embed a market-leading condition monitoring toolset that delivers much more than other systems on the market. The OEM sector is a significant market for us, and we can now enable companies to implement our technology in their products.”Installation of MCMSoC is straightforward with only one connection necessary to the motor or generator supply cables and no requirement for any specialist sensors on the equipment itself. MCMSoC has the added benefit of being suitable for a wide range of applications and devices including motor protection relays, current and circuit analysers, test equipment, event recorders, contactors, inverters, soft starters, and condition monitoring systems.MCMSoC provides the functionality of MCM in a single 40 pin PCB measuring 40mm X 50mm. It requires only six analog inputs representing three phase currents and voltages, and communicates using a high speed I/O port. A custom development package is also available to allow in-circuit emulation.About Artesis Artesis is a leading supplier of intelligent predictive maintenance solutions and has been offering its reliable and efficient range of products since 1999. Its technology has helped many customers around the world increase productivity and reduce maintenance costs. The Artesis team combines extensive experience in advanced product development with the successful application of advanced technology to the requirements of operations and maintenance professionals.Artesis manufactures a range of intelligent condition monitoring products including the Motor Condition Monitor (MCM), and Plant Condition Monitor (PCM) instruments, and the MCMSCADA software package. These products are used for plant monitoring, predictive maintenance, and process optimization across multiple industries including the chemical and petrochemical, metal processing, power generation, pulp and paper, water, utilities, cement, food and beverage, automotive, textile, and maritime sectors. Artesis has a robust intellectual property portfolio of issued and pending patents internationally.
To view the original page,click here.
Tuesday, January 13, 2009
用带电测试替代部分停电预防性试验的可行性探讨
文章引用来源：电子菜鸟天堂
http://zhao3367.spaces.eepw.com.cn/articles/trackback/item/26490
摘要：高压电气设备绝缘带电试验与常规停电试验相比具有较大的优越性。随着绝缘带电测试技术的逐步发展和完善，部分设备已经具备以带电测试取代传统停电预防性试验的条件。文中介绍了电容型设备和氧化锌避雷器的带电测试方法，并对其以带电测试代替预防性试验的可行性进行了探讨。
高压电气设备绝缘带电试验与常规停电试验相比具有较大的优越性：无需停电，测试灵活、方便；基于设备的运行状态，诊断绝缘缺陷的灵敏度高；试验周期可以依据设备绝缘状况灵活安排，便于及时发现设备的绝缘隐患，了解绝缘缺陷的变化趋势等。因此，电力设备绝缘带电试验技术的开发和应用，近年来逐渐得到重视。统计资料显示，现阶段国内高压绝缘带电试验工作主要集中在氧化锌避雷器、电容型设备（电容绝缘型电流互感器、套管、电容式电压互感器、耦合电容器等）、GIS局部放电等几个方面。随着绝缘带电测试技术的逐步发展和完善，部分设备已经具备以带电测试取代传统停电预防性试验的可能性，在新近出版的中国南方电网有限责任公司企业标准《电力设备预防性试验规程》中，也特别强调了带电测试的重要性，并就带电测试代替停电预防性试验作出了具体规定。 1．带电测试方法 （1）电容型设备 由于电容型设备是通过电容分布强制均压的，其绝缘利用系数较高，一旦绝缘受潮往往会引起绝缘介质损耗增加，导致击穿。因此，对电容型设备进行带电测试，对提高设备的运行维护水平、及时发现事故隐患、减少停电次数都能起到积极的作用。电容型设备介质损耗和电容量的变化对反映设备整体受潮、绝缘劣化等缺陷比较灵敏，绝缘受潮缺陷占电容型设备缺陷的85．4%，介质损耗和电容量测量一直是预防性试验的主要项目，也是带电（在线）检测技术开展最早的项目。
为了获得稳定的测量结果，可采用比较法测量进行带电测试，即选择一组电容型设备，以它的末屏电流信号作为参考标准，其他设备的末屏电流与其进行相对的测量，获取相对的介质损耗差值、电容量比值。这样，由于外部环境（如温度等）、运行情况（如负载容量等）变化而导致的测量结果波动会同时作用在标准设备和被试设备上，它们之问的相对测量值保持稳定，更容易反映设备绝缘的真实状况；同时，由于不需要采用二次侧电压作为参考信号，也不会由于PT角差的变化而对测量结果产生影响。
（2）氧化锌避雷器 氧化锌避雷器运行期间总有一定的泄漏电流通过阀片，加速阀片老化，而受潮和老化是氧化锌避雷器阀片劣化的主要原因。检测氧化锌避雷器泄漏全电流和阻性电流能有效地反映氧化锌避雷器的绝缘状况，全电流测量对于整体的受潮比较灵敏，早期老化阻性电流增加较多，全电流变化则不明显。所以测量交流泄漏电流及其有功分量是现场检测避雷器的主要方法，预防性试验规程也将氧化锌避雷器“运行中泄漏电流”的测量列入预防性试验项目。
当前，氧化锌避雷器带电测试的主要手段有：全电流在线监测、全电流及阻性电流带电测试和红外热成像测温等3种方法。各项检测手段具体实施方法存在很大差异，检测的有效性和灵敏度也各不相同。全电流及阻性电流带电测试是采用类似于测量电容型设备介质损耗的方式来检测氧化锌避雷器的泄漏电流及其阻性电流分量。全电流在线监测则仅测量泄漏电流全电流。氧化锌避雷器正常运行时阀片要通过一定的阻性泄漏电流分量，消耗一定功率，使本体有轻微发热，而且由于几何分布较均匀，所以外表发热也是整体性的。用红外热像仪进行故障诊断时，根据热像特征发现有不正常的发热、局部温度升高或降低，或者有不正常温度分布，则可以判断避雷器异常。因而，红外热成像测温作为一种非电测量方法也是检测避雷器缺陷和故障的有效手段。
2．带电测试代替预防性试验的可行性 国内外已进行的在线监测与带电测试经验表明，带电测试对检测结果的分析及发展趋势的判断更为重要。
（1）电流互感器 采用相对比较法带电测试方法多次对114相1lOkV电流互感器进行测试，结果表明，前后重复性很好并与停电预防性试验结果相近的占78．9%，前后重复性很好但与停电预防性试验结果有差别的占7．9%，前后重复性一般（但前后两次介损相对测量值差别也未超过±0．3%）的占13．2%；对9O相220kV电流互感器多次进行测试，结果表明，前后重复性较好并与停电预防性试验结果相近的占87．8%，前后重复性很好但与停电预防性试验结果有差别的占4．4%，前后重复性一般（但前后两次介损相对测量值差别也未超过±0．3%）的占7．8%。可见，采用相对比较法进行电流互感器带电测试与停电预防性试验具有很好的相关性，而且由于带电试验与停电试验存在许多不同之处，即使带电测试结果与停电试验有差异，只要前后多次带电测试数据保持稳定，并符合带电测试导则要求，就具备代替停电试验的条件。
（2）耦合电容器及电容式电压互感器 采用相对比较法带电测试方法多次对34相110kV电容式电压互感器进行测试，结果表明，前后重复性很好并与停电预防性试验结果相近的占35．3%，前后重复性很好但与停电预防性试验结果有差别的占29．4%，前后重复性一般的占35．3%；对14相1lOkV耦合电容器多次进行测试，结果表明，前后重复性很好并与停电预防性试验结果相近的占57．1%，前后重复性很好但与停电预防性试验结果有差别的占42．9%。可见，耦合电容器多次带电测试结果重复性都很好，只是部分与停电试验值比较有差异，已基本具备代替停电预防性试验的条件；电容式电压互感器由于结构较特殊，阻尼单元对测量结果影响较大，某些产品阻尼单元容易导致测量灵敏度降低，暂时还较难完全取代停电试验。
（3）氧化锌避雷器 氧化锌避雷器大都装有泄漏电流监测仪，运行中可随时巡检，观察其变化。该电流为通过避雷器的总电流，其中主要成分是容性电流，阻性电流所占成分较少。该电流与运行相电压、环境温度、相对湿度、污秽程度以及监测仪的特性都有关系，需要工作人员认真观察，并记录有关参数。当读数值比初始值增大20％时，应引起注意（还要参考当时运行电压）；若增大40％以上，应报缺陷，并尽快用专用仪器检测。
红外检测应采用红外热像仪，每月测量1次。由于温升不大，测温时应仔细观察分辨。测温前应查看避雷器电流监测仪的运行记录，对有问题的避雷器更应认真观察分辨。
当前，用于氧化锌避雷器阻性电流带电测试的仪器很多，各种仪器测量原理不尽相同，现场影响测量的因素也很多，所以对于测量结果的分析着重于历史数据的比较，长期测试结果能够反映避雷器绝缘的变化情况。测量时应记录电压、环境温度、大气湿度以及瓷套污秽状况等运行条件。影响现场测量结果的因素较多，如计数器内阻，测量仪器性能等，对系统标称电压220kV及以上的避雷器还应考虑邻相电场的影响。
一般情况下，能够坚持采用全电流在线监测、全电流及阻性电流带电测试及红外热成像测温这3种测试手段，便可实现氧化锌避雷器绝缘状态的检测，而替代常规停电预防性试验。2003年，广东电网通过全电流巡检、带电测试和红外检测发现了多起500kV避雷器缺陷。
本文引用通告地址：http://zhao3367.spaces.eepw.com.cn/articles/trackback/item/26490
http://zhao3367.spaces.eepw.com.cn/articles/trackback/item/26490
摘要：高压电气设备绝缘带电试验与常规停电试验相比具有较大的优越性。随着绝缘带电测试技术的逐步发展和完善，部分设备已经具备以带电测试取代传统停电预防性试验的条件。文中介绍了电容型设备和氧化锌避雷器的带电测试方法，并对其以带电测试代替预防性试验的可行性进行了探讨。
高压电气设备绝缘带电试验与常规停电试验相比具有较大的优越性：无需停电，测试灵活、方便；基于设备的运行状态，诊断绝缘缺陷的灵敏度高；试验周期可以依据设备绝缘状况灵活安排，便于及时发现设备的绝缘隐患，了解绝缘缺陷的变化趋势等。因此，电力设备绝缘带电试验技术的开发和应用，近年来逐渐得到重视。统计资料显示，现阶段国内高压绝缘带电试验工作主要集中在氧化锌避雷器、电容型设备（电容绝缘型电流互感器、套管、电容式电压互感器、耦合电容器等）、GIS局部放电等几个方面。随着绝缘带电测试技术的逐步发展和完善，部分设备已经具备以带电测试取代传统停电预防性试验的可能性，在新近出版的中国南方电网有限责任公司企业标准《电力设备预防性试验规程》中，也特别强调了带电测试的重要性，并就带电测试代替停电预防性试验作出了具体规定。 1．带电测试方法 （1）电容型设备 由于电容型设备是通过电容分布强制均压的，其绝缘利用系数较高，一旦绝缘受潮往往会引起绝缘介质损耗增加，导致击穿。因此，对电容型设备进行带电测试，对提高设备的运行维护水平、及时发现事故隐患、减少停电次数都能起到积极的作用。电容型设备介质损耗和电容量的变化对反映设备整体受潮、绝缘劣化等缺陷比较灵敏，绝缘受潮缺陷占电容型设备缺陷的85．4%，介质损耗和电容量测量一直是预防性试验的主要项目，也是带电（在线）检测技术开展最早的项目。
为了获得稳定的测量结果，可采用比较法测量进行带电测试，即选择一组电容型设备，以它的末屏电流信号作为参考标准，其他设备的末屏电流与其进行相对的测量，获取相对的介质损耗差值、电容量比值。这样，由于外部环境（如温度等）、运行情况（如负载容量等）变化而导致的测量结果波动会同时作用在标准设备和被试设备上，它们之问的相对测量值保持稳定，更容易反映设备绝缘的真实状况；同时，由于不需要采用二次侧电压作为参考信号，也不会由于PT角差的变化而对测量结果产生影响。
（2）氧化锌避雷器 氧化锌避雷器运行期间总有一定的泄漏电流通过阀片，加速阀片老化，而受潮和老化是氧化锌避雷器阀片劣化的主要原因。检测氧化锌避雷器泄漏全电流和阻性电流能有效地反映氧化锌避雷器的绝缘状况，全电流测量对于整体的受潮比较灵敏，早期老化阻性电流增加较多，全电流变化则不明显。所以测量交流泄漏电流及其有功分量是现场检测避雷器的主要方法，预防性试验规程也将氧化锌避雷器“运行中泄漏电流”的测量列入预防性试验项目。
当前，氧化锌避雷器带电测试的主要手段有：全电流在线监测、全电流及阻性电流带电测试和红外热成像测温等3种方法。各项检测手段具体实施方法存在很大差异，检测的有效性和灵敏度也各不相同。全电流及阻性电流带电测试是采用类似于测量电容型设备介质损耗的方式来检测氧化锌避雷器的泄漏电流及其阻性电流分量。全电流在线监测则仅测量泄漏电流全电流。氧化锌避雷器正常运行时阀片要通过一定的阻性泄漏电流分量，消耗一定功率，使本体有轻微发热，而且由于几何分布较均匀，所以外表发热也是整体性的。用红外热像仪进行故障诊断时，根据热像特征发现有不正常的发热、局部温度升高或降低，或者有不正常温度分布，则可以判断避雷器异常。因而，红外热成像测温作为一种非电测量方法也是检测避雷器缺陷和故障的有效手段。
2．带电测试代替预防性试验的可行性 国内外已进行的在线监测与带电测试经验表明，带电测试对检测结果的分析及发展趋势的判断更为重要。
（1）电流互感器 采用相对比较法带电测试方法多次对114相1lOkV电流互感器进行测试，结果表明，前后重复性很好并与停电预防性试验结果相近的占78．9%，前后重复性很好但与停电预防性试验结果有差别的占7．9%，前后重复性一般（但前后两次介损相对测量值差别也未超过±0．3%）的占13．2%；对9O相220kV电流互感器多次进行测试，结果表明，前后重复性较好并与停电预防性试验结果相近的占87．8%，前后重复性很好但与停电预防性试验结果有差别的占4．4%，前后重复性一般（但前后两次介损相对测量值差别也未超过±0．3%）的占7．8%。可见，采用相对比较法进行电流互感器带电测试与停电预防性试验具有很好的相关性，而且由于带电试验与停电试验存在许多不同之处，即使带电测试结果与停电试验有差异，只要前后多次带电测试数据保持稳定，并符合带电测试导则要求，就具备代替停电试验的条件。
（2）耦合电容器及电容式电压互感器 采用相对比较法带电测试方法多次对34相110kV电容式电压互感器进行测试，结果表明，前后重复性很好并与停电预防性试验结果相近的占35．3%，前后重复性很好但与停电预防性试验结果有差别的占29．4%，前后重复性一般的占35．3%；对14相1lOkV耦合电容器多次进行测试，结果表明，前后重复性很好并与停电预防性试验结果相近的占57．1%，前后重复性很好但与停电预防性试验结果有差别的占42．9%。可见，耦合电容器多次带电测试结果重复性都很好，只是部分与停电试验值比较有差异，已基本具备代替停电预防性试验的条件；电容式电压互感器由于结构较特殊，阻尼单元对测量结果影响较大，某些产品阻尼单元容易导致测量灵敏度降低，暂时还较难完全取代停电试验。
（3）氧化锌避雷器 氧化锌避雷器大都装有泄漏电流监测仪，运行中可随时巡检，观察其变化。该电流为通过避雷器的总电流，其中主要成分是容性电流，阻性电流所占成分较少。该电流与运行相电压、环境温度、相对湿度、污秽程度以及监测仪的特性都有关系，需要工作人员认真观察，并记录有关参数。当读数值比初始值增大20％时，应引起注意（还要参考当时运行电压）；若增大40％以上，应报缺陷，并尽快用专用仪器检测。
红外检测应采用红外热像仪，每月测量1次。由于温升不大，测温时应仔细观察分辨。测温前应查看避雷器电流监测仪的运行记录，对有问题的避雷器更应认真观察分辨。
当前，用于氧化锌避雷器阻性电流带电测试的仪器很多，各种仪器测量原理不尽相同，现场影响测量的因素也很多，所以对于测量结果的分析着重于历史数据的比较，长期测试结果能够反映避雷器绝缘的变化情况。测量时应记录电压、环境温度、大气湿度以及瓷套污秽状况等运行条件。影响现场测量结果的因素较多，如计数器内阻，测量仪器性能等，对系统标称电压220kV及以上的避雷器还应考虑邻相电场的影响。
一般情况下，能够坚持采用全电流在线监测、全电流及阻性电流带电测试及红外热成像测温这3种测试手段，便可实现氧化锌避雷器绝缘状态的检测，而替代常规停电预防性试验。2003年，广东电网通过全电流巡检、带电测试和红外检测发现了多起500kV避雷器缺陷。
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New power monitor annoucement
Summit Technology Inc, announces new power monitor models with SD memory card slot, CAT-IV safety rating, and Bluetooth wireless communications.
Smart PC SoftwareSetup files of different monitoring scenarios can be stored in your own "library" with PowerSight Manager software for the PC and then recalled to minimize set-up errors.
SureStartIntelligence in the meter checks your connections and alerts you to errors before you monitor. Result: no more bad data or wasted studies.
Analysis and ReportsPowerSight Manager software for the PC allows you to analyze graphs, zoom, expand, print, and export data to Excel.
Report Writer wizard automatically compiles a professional-looking, final report in a couple of mouse clicks. To see a completed report go here:
www.powersight.com/report
www.powersight.com/report
Thursday, January 8, 2009
Calibration system for electronic instrument transformers
A high-accuracy system for calibration of electronic instrument transformers with digital output is described. Its design is based on International Electrotechnical Commission (IEC) standards 61850, 60044-8, and 60044-7. The performance of the calibration system has been evaluated. Its estimated relative uncertainty (2σ) is within 40·10-6 in magnitude and within 40 μrad in phase.
Djokic, B. So, E. Inst. for Nat. Meas. Stand., Nat. Res. Council of Canada, Ottawa, Ont., Canada;
This paper appears in: Instrumentation and Measurement, IEEE Transactions on
Publication Date: April 2005Volume: 54, Issue: 2On page(s): 479- 482
ISSN: 0018-9456
INSPEC Accession Number: 8430618
Digital Object Identifier: 10.1109/TIM.2004.843420
Current Version Published: 2005-03-21
Djokic, B. So, E. Inst. for Nat. Meas. Stand., Nat. Res. Council of Canada, Ottawa, Ont., Canada;
This paper appears in: Instrumentation and Measurement, IEEE Transactions on
Publication Date: April 2005Volume: 54, Issue: 2On page(s): 479- 482
ISSN: 0018-9456
INSPEC Accession Number: 8430618
Digital Object Identifier: 10.1109/TIM.2004.843420
Current Version Published: 2005-03-21
Wednesday, January 7, 2009
Transformer & Switchgear PD Monitoring
Minimize the Risk of In Service Failure
During the last few decades, maintenance professionals have grown to appreciate the importance of monitoring medium voltage (4 kV to 28 kV) metal enclosed bus. Despite best efforts by manufacturers in the design of bus for indoor and outdoor applications, switchgear is not immune to aging and degradation mechanisms, particularly in industrial environments. Failure investigations reveal the link to electrical tracking between phases or phase-to-ground, and across non-metallic insulating components that support the bus.
The failure process involves contaminants (pollution) and moisture condensation. Accumulation of partly conductive airborne particles on the insulation surface results in the flow of capacitive currents that lead to discharges, and subsequently to the carbonization of organic components of the contaminants. Furthermore, poorly cast current transformers (CTs) and potential transformers (PTs) may have internal insulation voids. These voids result in partial discharge (PD) activity that will eventually bore a hole through the insulation and result in a failure to ground.
Improve Predictive Maintenance Program for your Switchgear
Traditional off-line methods of monitoring switchgear for PD activity require considerable investment (e.g. an expert to perform the measurement during scheduled outages). The techniques developed by Iris Power for motor and generator PD monitoring have now been extended to provide cost effective and reliable monitoring systems for metal clad switchgear and bus. The advantages to a maintenance department seeking to enhance reliability are as follows:
Low testing costs.
Once the sensors are installed, maintenance personnel perform periodic measurements during normal operation. In the case of a continuous monitor, the alarm levels are set to provide a warning of increasing PD activity.
Iris Power can provide support to assist in the installation and calibration of systems (if requested), and to help plan your outage by identifying the section(s) of the switchgear or bus duct that are at risk and require corrective action(s).
Trending of data and support with interpretation from Iris.
The instrumentation and hardware required to perform on-line PD testing on large rotating machines (i.e. motors and generators) is compatible with that required for bus monitoring. Hence, if your plant already owns the Iris TGAB technology, you can use the same test equipment and procedures for bus monitoring, improving the return on your investment.
What needs to be done to start monitoring PD on switchgear?
To find out what needs to be done to start monitoring PD on switchgear contact IRIS Power.
During the last few decades, maintenance professionals have grown to appreciate the importance of monitoring medium voltage (4 kV to 28 kV) metal enclosed bus. Despite best efforts by manufacturers in the design of bus for indoor and outdoor applications, switchgear is not immune to aging and degradation mechanisms, particularly in industrial environments. Failure investigations reveal the link to electrical tracking between phases or phase-to-ground, and across non-metallic insulating components that support the bus.
The failure process involves contaminants (pollution) and moisture condensation. Accumulation of partly conductive airborne particles on the insulation surface results in the flow of capacitive currents that lead to discharges, and subsequently to the carbonization of organic components of the contaminants. Furthermore, poorly cast current transformers (CTs) and potential transformers (PTs) may have internal insulation voids. These voids result in partial discharge (PD) activity that will eventually bore a hole through the insulation and result in a failure to ground.
Improve Predictive Maintenance Program for your Switchgear
Traditional off-line methods of monitoring switchgear for PD activity require considerable investment (e.g. an expert to perform the measurement during scheduled outages). The techniques developed by Iris Power for motor and generator PD monitoring have now been extended to provide cost effective and reliable monitoring systems for metal clad switchgear and bus. The advantages to a maintenance department seeking to enhance reliability are as follows:
Low testing costs.
Once the sensors are installed, maintenance personnel perform periodic measurements during normal operation. In the case of a continuous monitor, the alarm levels are set to provide a warning of increasing PD activity.
Iris Power can provide support to assist in the installation and calibration of systems (if requested), and to help plan your outage by identifying the section(s) of the switchgear or bus duct that are at risk and require corrective action(s).
Trending of data and support with interpretation from Iris.
The instrumentation and hardware required to perform on-line PD testing on large rotating machines (i.e. motors and generators) is compatible with that required for bus monitoring. Hence, if your plant already owns the Iris TGAB technology, you can use the same test equipment and procedures for bus monitoring, improving the return on your investment.
What needs to be done to start monitoring PD on switchgear?
To find out what needs to be done to start monitoring PD on switchgear contact IRIS Power.
Flaw Testing for Power Generation
Ultrasonic Testing
Ultrasonic gages are commonly used in both fossil and nuclear power plants for measuring and documenting the effects of corrosion and erosion on steam boiler tubes, and also for measuring the thickness of the internal oxide buildup that limits tube life. In-service cracking in pipes, boiler tubes, steam lines, and reactor vessels can be identified with ultrasonic flaw detectors and phased array systems, which can also be used for locating cracking in generator turbine blades and rotors.
Eddy Current Testing
Eddy current technology is important to the power generation industry, particularly for the inspection of tube bundles used in the cooling process. The bundles being inspected can include many thousands of tubes, all requiring inspection, analyzing and cataloging. With projects like these, the eddy current technology is coupled with complex inspection recording programs like Carto, which allows the operators to complete the tube inspection and record the results for each tube and compile these results into a simple and easy-to-read report.
Remote Visual Inspection
RVI helps engineers get to the heart of problems quickly and easily, by checking for pitting, cracking, corrosion, erosion, weld and other defects, thus minimizing downtime and optimizing planned maintenance. If access to plant is via ladders, catwalks and into cramped spaces, portability is obviously important.
Olympus Industrial has a wide selection of lightweight, compact, yet versatile inspection systems, to suit most industrial environments and products, providing high resolution imaging in compact and mobile packages, where portability is enhanced with battery operation.
for more, visit http://www.olympus-ims.com
Ultrasonic gages are commonly used in both fossil and nuclear power plants for measuring and documenting the effects of corrosion and erosion on steam boiler tubes, and also for measuring the thickness of the internal oxide buildup that limits tube life. In-service cracking in pipes, boiler tubes, steam lines, and reactor vessels can be identified with ultrasonic flaw detectors and phased array systems, which can also be used for locating cracking in generator turbine blades and rotors.
Eddy Current Testing
Eddy current technology is important to the power generation industry, particularly for the inspection of tube bundles used in the cooling process. The bundles being inspected can include many thousands of tubes, all requiring inspection, analyzing and cataloging. With projects like these, the eddy current technology is coupled with complex inspection recording programs like Carto, which allows the operators to complete the tube inspection and record the results for each tube and compile these results into a simple and easy-to-read report.
Remote Visual Inspection
RVI helps engineers get to the heart of problems quickly and easily, by checking for pitting, cracking, corrosion, erosion, weld and other defects, thus minimizing downtime and optimizing planned maintenance. If access to plant is via ladders, catwalks and into cramped spaces, portability is obviously important.
Olympus Industrial has a wide selection of lightweight, compact, yet versatile inspection systems, to suit most industrial environments and products, providing high resolution imaging in compact and mobile packages, where portability is enhanced with battery operation.
for more, visit http://www.olympus-ims.com
Sunday, January 4, 2009
Nexus® 1500 Meter: Advanced Power Quality Monitoring & Communication
General Features
0.06% Revenue Energy Accuracy
Accu-Measure™ Auto-Calibrating Technology
20 Year TOU Calendar
Load Profile
Pulse Aggregation
Demand Control
0.06% Revenue Energy Accuracy
Accu-Measure™ Auto-Calibrating Technology
20 Year TOU Calendar
Load Profile
Pulse Aggregation
Demand Control
Communication and User Interface
• Standard 10/100BaseT Ethernet Port
• Expandable Serial Ports (Dual RS485 Ports)
• Modbus, Modbus TCP, DNP 3.0 Level 2
• 8 Simultaneous Connections via Ethernet
• Optional Second Ethernet Port
• Vivid 256 Color Display
• Optional 100BaseT Fiber Port
• Data Download Speed 20 Times Faster Than Existing Technology
New Generation Transient Recording Power Quality
• 10MHz Transient Recorder (166,000 Samples per Cycle)
• 8 Channel Waveform Recorder
• Voltage Surge, Sag and Transient Recording
• Current Fault Signatures and Analysis
• 1 Gigabyte Memory – Highly Extensive Recording Capability
for full description of the products, please address here.
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