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绕组压紧状态影响着变压器的机械性能和绝缘性能。为此,提出一种基于奇异谱熵和支持向量机的变压器绕组松动诊断及定位方法。首先进行110 kV变压器绕组松动实验并测取不同绕组状态下的振动信号,对信号进行时间序列重构,通过奇异值分解提取重构空间的最优特征序列,结合信息熵得出绕组松动的特征量——奇异谱熵,并作为诊断模型的输入,利用粒子群算法对多分类支持向量机进行参数优化。并将其测试结果与BP和PNN神经网络的诊断效果进行对比。实验结果证明,该方法能有效地判断绕组是否发生松动并正确识别绕组松动相,验证了上述方法的可行性和准确性。 相似文献
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针对变压器绕组松动故障诊断中特征量难以选取,依赖人工经验的问题,提出了一种基于自动编码器降噪,格拉姆角场(GAF)和深度残差网络(ResNet)进行识别的变压器绕组松动诊断方法。该方法直接从GAF图像中自动学习有效的故障特征,不需要手动提取特征量。首先,将振动信号经过自动编码器进行降噪,获得信噪比更高的振动信号。然后,采用GAF方法将振动信号转化为二维图像,生成图像数据集,在此基础上训练ResNet,构建适用于变压器绕组松动故障分类识别的网络模型。最后,搭建变压器绕组松动故障试验平台,采集绕组在不同松动和试验电流下的振动信号并进行分析。试验结果表明,所提诊断方法对变压器绕组松动识别准确率达95%以上,能够有效识别松动相和松动程度,适用于变压器绕组松动故障的识别和诊断。 相似文献
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《中国电机工程学报》2016,(9)
为进一步理解和掌握变压器绕组的振动特性,通过建立实体变压器的三维有限元分析模型,使用超弹性Mooney-Rivlin模型模拟变压器绕组垫块的非线性材料特性,基于"磁–机械"耦合场理论实现了变压器运行过程中由电动力激励到绕组振动响应的全过程仿真分析,得到了变压器绕组在电磁力激励下正常与松动状态下的振动特性。对某35 k V电力变压器振动特性的测试结果表明,变压器绕组振动波形的计算结果与直接布置于绕组上的光振传感器的测试结果吻合良好,验证了计算结果的正确性。此外,变压器绕组松动即预紧力的下降相当于垫块材料刚度的增加,此时,绕组振动信号中的100 Hz分量及其倍频均随之增大,但增幅各异。研究结果可为变压器绕组结构优化及绕组变形振动检测法提供重要依据。 相似文献
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Rauls M.S. Novotny D.W. Divan D.M. Bacon R.R. Gascoigne R.W. 《Industry Applications, IEEE Transactions on》1995,31(1):112-118
Previous papers on coaxial winding transformers have focused on designs that use a copper tube to form a single-turn outer winding, and litz wire for a multiple-turn inner winding. In high-power applications, the increased resistance of a solid outer winding due to skin effects can be a limiting factor in achieving good performance, especially at frequencies above several hundred kilohertz. A single-turn outer winding leads to large core cross section areas at lower frequencies and the turns ratio is limited to a ratio of n:1, where n is an integer. This paper demonstrates several methods for achieving multiturn outer windings to improve design flexibility for the coaxial winding power transformer. Experimental measurements on transformers that have multiturn outer windings are included to confirm analytical results and demonstrate the modified designs 相似文献
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Moonhee Lee Hussein A. AbdullahJan C. Jofriet Dhiru PatelMurat Fahrioglu 《Electric Power Systems Research》2011,81(3):783-789
The temperature of the air surrounding the windings of ventilated dry-type transformers is an important factor in the cooling of the windings since they are cooled only by the air. In particular, inner windings are sensitive to the air temperature in vertical cooling ducts. This study presents air temperature effect on the temperatures in foil-type inner winding for the dry-type transformers. A transformer rated at 2000 kVA was selected for the research and temperature distribution was calculated under constant and varying air temperatures inside vertical ducts at three different loads. The 2-D transient heat diffusion equation was solved using the finite element method by coupling it with the vector potential equation due to non-uniformly generated heat caused by eddy currents in the foil winding. The calculated temperatures at constant and varying air temperatures are presented together with experimental values. The numerical and experimental results of this study showed that the air temperature affects the accuracy of temperatures in foil-type inner winding greatly. 相似文献
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发电机变压器放电故障诊断的基础研究和应用 总被引:8,自引:1,他引:8
检测电气设备的局部放电(PD)信息,诊断绝缘故障,可避免严重后果.作为绕组类设备,当发电机和变压器内发生局部放电时,由于PD脉冲沿绕组的传播,在绕组两端检测得到的放电信号将被畸变.从工程应用的角度看,需要解决PD信号的检测和量化、PD源定位、故障模式判断及干扰抑制问题.因此,需要深入研究的基础内容包括:放电脉冲信号特征,脉冲沿绕组的传播规律,现场强烈电磁干扰的抑制,放电故障模式识别等.文中综合介绍国内外在以上各方面所取得的成果,并提出今后需进一步开展研究的几方面内容:基础研究成果的工程实用,远程诊断,多故障模式识别和模糊诊断等. 相似文献
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N. P. Grigor’ev A. V. Voprikov A. P. Parfianovich 《Russian Electrical Engineering》2016,87(2):100-103
Upgrading the traction power supply is an important task in developing railway power engineering. The Russian railway transport development strategy envisions updating power supply equipment, including the reconstruction of 763 traction substations, which will be very expensive. Power transformers are the main, and most expensive, apparatuses in traction substations. They account for more than 50% of the cost of substation equipment. Steps in increasing the operating life of power traction substations during upgrading the ac traction substations are described in the present article. Substation upgrading involves up-to-date equipment and technologies. The decision to replace or further use existing substation power transformers is primarily based on data on the real condition of transformers. The 25 kV alternating current power transformers traction substations operate with the high unbalanced current of windings. The current of the most loaded winding can possess double magnitude of currents in other windings, while the losses of windings differ by four times. A qualitative analysis of transformer operating life based on insulation wear for three traction substations is presented. The winding with maximum insulation wear is assessed on the basis of power consumption. In order to extend the operating life, windings need to be connected to neutral links of a traction substation. 相似文献
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自耦补偿与谐波屏蔽换流变压器的接线方案和原理研究 总被引:29,自引:5,他引:24
针对传统换流变压器和滤波方式存在的问题,对一种新型的自耦补偿与谐波屏蔽换流变压器进行研究.该换流变压器阀侧绕组采用延边三角形接线,为3倍次谐波电流提供通路;通过匝比配合,实现12脉波换流;其延边绕组与公共绕组构成自耦变压器接线,可减少换流器换向时的电流冲击;在公共绕组上连接滤波支路,并调至谐振点,配之以变压器巧妙的零阻抗设计,可以在阀侧实现无功补偿,可实现网侧绕组中无5、7、11、13次特征谐波,即谐波屏蔽.仿真结果表明论文的理论分析正确;这种新型换流变压器可大大减少网侧绕组中的谐波含量,降低谐波在变压器中引起的损耗和噪音,同时可降低换流变压器的设计容量和绝缘设计的难度,将有很好的应用前景. 相似文献
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Mehdi NafarTaher Niknam Amirhossein Gheisari 《International Journal of Electrical Power & Energy Systems》2011,33(3):493-499
Most serious failure of power transformers is due to the insulation breakdown. Partial discharge (PD) that damages insulation by gradual erosion is major source of insulation failure. The effective ability of the wavelet packets analysis as a tool for disk-to-disk partial discharge faults detection and localization in transformer windings is shown in this paper. Techniques for locating a PD source are of the major importance in both the maintenance and repair of a transformer. One of the most well-known methods of PD localization in transformers is based on winding modeling and current of neutral point analysis. Since the impedance between PD location and neutral point of winding depends on the PD location in respect to neutral point, the frequency spectrum of neutral point current varies when the PD location changes. In the other word, the current components of neutral points vary according to the place where PD occurs. So in this paper, detailed model of transformer winding is modeled and the neutral point current is studied for locating PD. The used method is validated by the simulated model of transformer windings. This model produces a very acceptable current when compared to the experimental data. In this paper for locating partial discharge (PD) in transformer windings, a simulated model is developed for the transformer winding and the PD phenomenon mechanism. The impulse current test and wavelet packets transformation are used to locate PD. It is shown that the neutral current measurement of the transformer winding has useful information about PD location. 相似文献
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从变压器事故实例看短路试验的必要性 总被引:2,自引:0,他引:2
在电力系统中,大型变压器因绕组抗短路强度不足造成绕组失稳损坏事故愈来愈突出。本文通过实例分析了绕组受力情况和损坏原因,指出只有对产品进行短路试验,找出薄弱环节加以改进,才能提高变压器抗短路强度,并提出了抗短路强度的主要措施。 相似文献
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针对电网对变压器绕组健康状态在线监测的需求,提出了一种新的变压器绕组变形故障在线监测方法。通过在线测量两种不同负荷下一次侧和二次侧的电压电流,计算出变压器的短路电抗值,进而反映变压器绕组变形情况。此方法的突出优势在于无需空载调零,不受激磁电流变化影响,不受运行中配电变压器一次侧电压随电网电压波动的影响且精度很高。将所提方法应用于不同容量的配电变压器,仿真结果显示该方法能够精确有效地在线测量正常变压器和有不同程度变形故障的变压器的短路电抗值,从而实现配电变压器绕组变形故障的在线监测。依据本方法的特点,设计了实现短路电抗在线监测所必需的数据采集模块和分析模块。 相似文献