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运行中发现,变电所不接地系统电压互感器二次电压会出现不平衡现象,运行人员往往把这种现象认为是一次系统接地,其实不尽然.本文对电压互感器二次电压不平衡的原因进行了分析,提出了判断方法。 相似文献
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针对主变压器冲击试验时低压侧二次电压三相不平衡现象,实测各种工况下二次电压幅值,对比各次谐波含量,分析谐波谐振对二次电压不平衡现象的影响,验证了在主变低压侧电压互感器中性点增设消谐器可以明显改善二次电压三相不平衡现象。 相似文献
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中性点不接地系统电压不平衡现象分析 总被引:1,自引:0,他引:1
结合薛家湾供电局变电站运行的实际,对110kV及以下变电站中性点不接地系统电压不平衡的现象进行了分析,阐明了产生这些现象的原因,对保证系统安全稳定运行具有指导意义。 相似文献
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配网中三相电压不平衡现象是电网异常和故障的反映,其产生原因、机理和事故现象多种多样。文中对配网中三相电压不平衡现象的成因进行了分析,归纳和总结了各种三相电压不平衡故障的处理方法。为调度员迅速、准确处理三相电压不平衡故障提供了参考和帮助。 相似文献
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解决35kV母线三相不平衡电压的措施 总被引:1,自引:1,他引:0
在实际电网中存在着各相对地电容不平衡,尤其是中相电容偏低的现象,这是造成母线三相不平衡的主要因素。对电容不平衡进行合理的补偿可有效地解决这一问题。文章从理论分析入手,并介绍了中相补偿,分散补偿的实施细节,以及其技术,经济的效果。 相似文献
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正确判断造成系统电压不平衡现象的原因,有利于正确及时地处理系统故障。分析了变压器高压缺相、电压互感器一次或二次侧熔丝熔断、中性点不接地系统单相接地等产生电压不平衡现象的特点,进行故障分析和判断。 相似文献
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本文中作者根据陕西榆林电厂主变倒送电试验,对试验中出现的发电机PT二次电压不平衡现象和作者所采取的有关措施以及试验数据进行了详细的分析,从理论角度分析了出现电压不平衡的原因,并给出了解决办法。 相似文献
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—High phase order systems have been proposed at the early inception of power transmission engineering, but few direct applications have been made. High phase order transmission should be considered as an alternative in the case of high power density applications. In this article, an analysis of transposition of high phase order overhead transmission lines is presented and voltage unbalance in high phase order systems is considered. Definitions are presented for “fully transposed” and “roll transposed” along with advantages and disadvantages of each. A generalized voltage unbalance factor is introduced and utilized to determine the benefits of transposition. The generalized voltage unbalance factor is compared with three other possible unbalance factors to determine if the generalized voltage unbalance factor is an appropriate indication of unbalance. Exemplary results are presented for 6-phase and 12-phase designs. Conclusions show that the generalized voltage unbalance factor is a good indication of transmission line voltage unbalance and certain configurations may not need full rotation transposition to minimize the unbalance factor. The transposition analysis and voltage unbalance are considerations in the assessment of high phase order as a high power transmission alternative. 相似文献
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Analysis of Measured Data in Unbalanced Distribution System and Method of Making of Distribution System Model for Analyzing 下载免费PDF全文
YU FUJITA HIROSHI KOBAYASHI TAKANORI KODERA MUTSUMI AOKI HIROTO SUZUKI HIROYUKI ISHIKAWA TAKURO MIWA 《Electrical Engineering in Japan》2017,199(1):19-27
In recent years, rapid introduction of photovoltaic power systems (PVs) causes voltage rise in distribution systems. In addition, residential PVs cause voltage unbalance in distribution systems. For these reasons, it has become difficult to control voltage in distribution systems to within the allowable range. Therefore, it is necessary to consider the voltage unbalance suppression method corresponding to the measured data in unbalanced distribution systems. Thus, we measured voltage on the distribution lines that are expected to large voltage imbalance and analyzed the reality of voltage unbalance. Also, static VAR compensator is suitable for voltage unbalance suppression, although it is expensive. Therefore, we make the distribution system model using the measured voltage in distribution systems to verify the voltage unbalance suppression effect. 相似文献
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A STATCOM is expected to be suitable for use as voltage control equipment for a distribution system that needs to be controlled to suppress the voltage deviation caused by an increase in the number of photovoltaic energy sources. A Y‐connected MMC is a promising alternative for the STATCOM circuit topology. However, it is known that the Y‐connected MMC cannot achieve capacitor voltage balance between phases with unbalance current output in order to compensate system voltage unbalance. To solve this problem, we propose a novel method to control the capacitor voltage for unbalance current output. The proposed control involves feedforward and feedback zero sequence voltage control. The feedforward control prevents capacitor voltage unbalance between phases, which is caused by the unbalance current that the Y‐connected MMC outputs. The feedback control cancels the remaining control error of the feedforward control. We verified the performance of this control through transient simulation. The Y‐connected MMC with the proposed control can realize capacitor voltage balance between phases even when the Y‐connected MMC outputs an unbalance current. Additionally, we determined the maximum unbalance current output produced by the Y‐connected MMC in relation to the rated capacitor voltage. 相似文献
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In this paper, various definitions of voltage unbalance are explored and compared, and their proper application conditions are examined as well. A popular optimal algorithm, the genetic algorithm, is adopted to investigate the differences among various definitions of voltage unbalance. By fixing the numerical value of the concerned definition of voltage unbalance, the maximum and minimum values of the true definition of voltage unbalance are found and compared. Finally, suitable conditions to apply the definitions are drawn. 相似文献
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不平衡保护是预防电容器组故障的主要保护,文章介绍了不平衡保护的方式,分析了不平衡电压产生的原因,井通过实例时并联电容器组不平衡电压进行了模拟仿真、分析以确保不平衡保护整定值的可靠性。 相似文献
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并联电容器组不平衡保护整定值的确定 总被引:2,自引:2,他引:0
黎林 《电力电容器与无功补偿》2010,31(6)
不平衡保护是预防电容器组故障的主要保护,文章介绍了不平衡保护的方式,分析了不平衡电压产生的原因,并通过实例对并联电容器组不平衡电压进行了模拟仿真、分析以确保不平衡保护整定值的可靠性。 相似文献
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The effect of voltage unbalance in electrical networks that supply electrified traction loads on the operating regimes of large asynchronous motors (AMs) is considered. Based on the method of symmetrical components and analysis of hodographs of magnetic fields of AMs with a short squirrel-cage rotor, the influence of various types of voltage unbalance (continuous and intermittent) on its vibration characteristics is studied. It is shown that an increase in magnetic induction in the air gap of an AM causes an increase in radial vibration generating forces in the case of voltage unbalance. The obtained results indicate that alternating voltage unbalance can be riskier for AM operation than is constant voltage unbalance, in addition to having increased levels of AM vibrations. It is concluded that the use of new parameters of electric-energy quality allowing determination of instantaneous values of unbalance amplitude and the angle between symmetrical components of voltage of positive and negative phase-sequence is reasonable. The relevance of this research is confirmed by typical cases of AM shutoff at an oil-pumping station due to tripping of vibration-protection sensors. 相似文献
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L. Fernando. Mantilla 《Electrical Engineering (Archiv fur Elektrotechnik)》2007,89(7):535-545
Induction motors operating under a given unbalance factor have very different supply voltage conditions. This article presents
a complete and precise analysis about the whole range of the amplitude and phase variation of the supply symmetrical components
in relation to the values of the voltage unbalance parameters. The exact formulation and graphical representation of the supply
voltage sequence components for a given unbalance parameter is shown. 相似文献