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牵引负荷对变压器绝缘老化和寿命损失的影响 总被引:4,自引:0,他引:4
在分析牵引负荷特点和变压器绝缘老化机理的基础上,提出了绕组热点温升与牵引变压器绝缘寿命损失之间的关系式。仿真研究了经典牵引负荷下的绕组热点温升,计算了绕组热点温升引起的绝缘寿命损失;依据仿真结果建立了牵引变压器受冲击负荷影响的模拟实验系统,通过监测、分析冲击负荷和等值负荷2种情况下油中溶解CO和CO2含量的变化情况,得到了热冲击对绝缘老化的影响关系。研究结果表明牵引冲击性负荷对变压器绝缘寿命损失影响很大,不容忽视。 相似文献
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在分析牵引负荷特点和变压器绝缘老化机理的基础上,提出了绕组热点温升与牵引变压器绝缘寿命损失之间的关系式。仿真研究了经典牵引负荷下的绕组热点温升,计算了绕组热点温升引起的绝缘寿命损失;依据仿真结果建立了牵引变压器受冲击负荷影响的模拟实验系统,通过监测、分析冲击负荷和等值负荷2种情况下油中溶解CO和CO2含量的变化情况,得到了热冲击对绝缘老化的影响关系。研究结果表明牵引冲击性负荷对变压器绝缘寿命损失影响很大,不容忽视。 相似文献
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深海环境为散热提供了有利条件,因此水下机器人装配的环形变压器可以具备更高的功率密度和损耗.为研究环形变压器在水下环境的温升情况,结合热路理论及其散热结构,建立相应的稳态热路模型.以14.3 kVA的单相中频环形变压器为研究对象,将热路模型计算所得结果与Fluent有限元软件仿真和温升试验结果进行比较.结果 表明:热路模型计算结果与二者之间的误差在6%以内,同时与有限元仿真相比,使用热路模型计算的分析过程更为简单.所提出的热路模型适用于深海环形变压器的温升分析. 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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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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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
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本文提出了变压器线圈涡流损耗的解析算法,给出了变压器窗口漏磁场及导体涡流损耗的解析公式,讨论了双重富氏级数收敛项数的选择,并以两台具有短路损耗实测值的变压器为例进行了计算、对比. 相似文献
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Mabel Ebenezer Rajkumar Mattacaud Ramachandralal Chandramohanan Nair Padmanabha Pillai Sarasamma 《电力部件与系统》2015,43(20):2251-2261
Transformers are critical components in power systems and their failure can cause long interruption of power supply. The condition of a transformer can be monitored by performing thermal analysis. The use of non-linear devices, such as rectifiers and converters, draws harmonic currents that increase losses in transformers, thereby increasing their operating temperature. In this article, a new numerical approach is presented for determining the rise in hot spot temperature in a 5-kVA, 400/400-V dry-type three-phase transformer laboratory prototype. The key novelty is that the additional winding eddy current loss due to non-linear loads is considered in the numerical modeling. The winding eddy current loss corresponding to harmonic distortion is estimated by conducting experiments and calculations. Numerical simulations are carried out for a wide range of non-linear loads using a commercial computational fluid dynamics package, FLUENT 6.3. The proposed numerical methodology is validated by performing experiments on the transformer for possible non-linear loads and comparing the measured hot spot temperature with the simulated values. Correlation equations for rise in hot spot temperature as a function of total harmonic distortion are presented, which can be used for estimating the life of transformers when connected to different types of loads. 相似文献
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Abstract—To insure the health of power transformers insulation, its heat distribution in different operating conditions must be determined. In extended thermal equivalent circuits (TECs), less attention has been paid to losses and temperature distribution of different parts such as core, tank and metallic regions of transformer. Most previous works, hot-spot temperature of winding and top-oil were considered by available no-load and on-load losses of transformer. This paper extends the TEC to be able to evaluate fully the different operating conditions of transformer. Estimation of losses of different elements of transformer as heat generating source and thermal parameters of transformer are introduced as two major challenges of the proposed model. At this end, an appropriate three-dimensional finite element method is used to estimate the losses of different components of power transformer. In addition, to identify the transformer thermal parameters, a genetic algorithm is used by searching in chosen measurements. Finally, the results obtained by the TEC are compared with IEEE-Annex G method and measured temperature and high accuracy of the proposed model in temperature estimation in different parts of transformer are shown. 相似文献
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Specially connected transformers such as V–V, Scott and Le-Blanc transformers are used to convert a three-phase supply into one or two single-phase supplies. These transformers are commonly used in the electro locomotive traction systems. This paper investigates the harmonic cancellation characteristics of such transformers. The results show that when two harmonic-producing loads are connected to each single-phase side of the transformers, the harmonics produced by the loads will cancel out at the primary sides of the transformers. The amount of cancellation is affected by transformer type and harmonic order. The study is performed for seven types of specially connected transformers. 相似文献
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油浸式电流互感器一次绕组温升特性的计算与分析 总被引:1,自引:0,他引:1
分析了油浸式电流互感器一次绕组内外变压器油的流动与换热特性,提出了一套计算其流动与温升特性的数学模型,并研制了通用计算机软件。计算结果与不同规格、不同工况的产品试验结果基本一致。该计算方法和软件对提高油浸式电流互感器热设计水平、保证产品可靠性具有重要意义。该方法原则上也适用其他流体( 如SF6) 作为绝缘介质的互感器热性能计算与分析。 相似文献