共查询到20条相似文献,搜索用时 250 毫秒
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根据特高压变压器差动保护的要求,提出了一种基于附加相位判别的自适应2次谐波励磁涌流制动方案。该方案充分利用涌流波形中的幅值相位信息,改善了某些涌流不明显情况下传统2次谐波制动原理的不足,同时空投变压器内部故障时也不会误闭锁差动保护。各种情况下的仿真与动模数据的测试结果表明:自适应附加相位制动方案的差动保护比传统2次谐波判据性能优良,且有较好的实际工程应用价值。 相似文献
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基于附加相位判别的自适应二次谐波励磁涌流制动方案研究 总被引:7,自引:4,他引:7
在详细推导单相励磁涌流的傅里叶级数表达式基础上,分析出涌流波形中各次谐波之间满足一定的相位关系,即单相涌流中基波相位与2次谐波相位差为0°或180°,由此提出了一种基于附加相位判别的自适应2次谐波励磁涌流制动方案。该方案充分利用涌流波形中的幅值相位信息,改善了某些涌流不明显情况下传统2次谐波制动原理的不足,同时空投变压器内部故障时也不会误闭锁差动保护。各种情况下的仿真与动模数据的测试结果表明:自适应附加相位制动方案的差动保护比传统2次谐波判据性能优良,且有较好的实际工程应用价值。 相似文献
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李本瑜 《电力系统保护与控制》2004,32(15):74-75
在《整定导则》中推荐的二次谐波制动系数为15%~20%,该制动系数是以两相涌流之差为基础分析得出的,鉴于RCS 978微机变压器差动保护对变压器各侧电流相位补偿方法的独特之处,励磁涌流在RCS 978差动保护装置中以相电流的形式出现,而非两相涌流之差,分析了《整定导则》中推荐的二次谐波制动系数用于RCS 978变压器差动保护装置时可能存在的问题。 相似文献
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介绍一种微机型电力变压器差动保护装置。该装置利用微型计算机快速检测、准确判断的智能特点,通过检测变压器回路断路器的运行状态,对变压器施以相应的控制方式。如果变压器已处于正常运行状态。则微机对差动保护回路的差动电流和制动电流进行检测、比较,从而判别变压器的内部与外部故障。如果制动电流大于差动电流,则判定为变压器正常运行或外部故障,差动保护不动作;如果制动电流小于差动电流,则判别为变压器内部故障,保护装置即发出变压器跳闸命令脉冲。如果检测到变压器处于停运状态,则由微机继续监测变压器状态,一旦发生变压器投运则利用kalmanfilter对变压器回路电流进行滤波分析。通过对直流偏移、基波分量及二次谐波分量的检测、比较,来判别变压器的励磁涌流和投运于内部故障。如果判定为非投运于内部故障,则利用二次谐波的制动原理,使差动保护有效地躲过励磁涌流而不致于误动作。本装置的主要优,或是可以成功地躲过变压器空载投运时的励磁涌流和变压器外部短路时的不平衡电流而不致于降低保护装置的灵敏度。同时,由于实施了微机控制,本差动保护较之传统的差动保护检测精确,判断准确,动作可靠性高。 相似文献
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李本瑜 《电力系统保护与控制》2004,32(15)
在<整定导则>中推荐的二次谐波制动系数为15%~20%,该制动系数是以两相涌流之差为基础分析得出的,鉴于RCS-978微机变压器差动保护对变压器各侧电流相位补偿方法的独特之处,励磁涌流在RCS-978差动保护装置中以相电流的形式出现,而非两相涌流之差,分析了<整定导则>中推荐的二次谐波制动系数用于RCS-978变压器差动保护装置时可能存在的问题. 相似文献
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用相关分析法识别变压器励磁涌流的研究 总被引:1,自引:0,他引:1
提出了用相关分析法和模糊集理论来识别故障电流及励磁涌流的新方法。论证了该原理与谐波制动原理之间的对应关系,证明了辨识对称涌流的有效性。模拟实验结果表明:本方法可准确识别故障电流和励磁涌流;即使在空载合闸于内部短路故障时,保护继电器也能迅速可靠动作,避免了采用二次谐波制动导致的拒动问题。 相似文献
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Myong-Chul Shin Chul-Won Park Jong-Hyung Kim 《Power Delivery, IEEE Transactions on》2003,18(3):718-724
Power transformer protective relay should block the tripping during magnetizing inrush and rapidly operate the tripping during internal faults. The frequency environment of power system has been made more complicated and the quantity of 2nd frequency component in inrush state has been decreased because of the improvement of core steel. Then, traditional approaches will likely be maloperated in the case of magnetizing inrush with low second harmonic component and internal faults with high second harmonic component. This paper proposes a new relaying algorithm to enhance the fault detection sensitivities of conventional techniques by using a fuzzy logic approach. The proposed fuzzy-based relaying algorithm consists of flux-differential current derivative curve, harmonic restraint, and percentage differential characteristic curve. The proposed relaying was tested with relaying signals obtained from Salford EMTP simulation package and showed a fast and accurate trip operation. 相似文献
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D.B. Fakruddin K. Parthasarathy L. Jenkins B.W. Hogg 《International Journal of Electrical Power & Energy Systems》1984,6(3):169-180
The development of algorithms, based on Haar functions, for extracting the desired frequency components from transient power-system relaying signals is presented. The applications of these algorithms to impedance detection in transmission line protection and to harmonic restraint in transformer differential protection are discussed. For transmission line protection, three modes of application of the Haar algorithms are described: a full-cycle window algorithm, an approximate full-cycle window algorithm, and a half-cycle window algorithm. For power transformer differential protection, the combined second and fifth harmonic magnitude of the differential current is compared with that of fundamental to arrive at a trip decision. The proposed line protection algorithms are evaluated, under different fault conditions, using realistic relaying signals obtained from transient analysis conducted on a model 400 kV, 3-phase system. The transformer differential protection algorithms are also evaluated using a variety of simulated inrush and internal fault signals. 相似文献
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用模糊集贴近度法识别变压器的故障电流和励磁涌流 总被引:1,自引:0,他引:1
根据电力变压器差动保护中故障电流和励磁涌流波形的对称情况,提出了用波形对称及模糊集贴近度原理来辨别故障电流和励磁涌流的新方法。数字仿真结果表明,本方法可准确识别故障电流和励磁涌流,即使在空载合闸于内部故障时,保护继电器也能迅速可靠动作,避免了采用二次谐波制动导致的误动问题。 相似文献
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The design and real-time implementation of a Kalman-filter-based digital percentage differential and a ground-fault protection scheme for three-phase power transformers are presented. A set of eleven-state Kalman filters is used to estimate the fundamental and up to fifth harmonic components of the transformer current signals. The protective relay is equipped with an even harmonic restraint during magnetizing inrush conditions and a fifth harmonic restraint during overexcitation conditions. The restraint during external faults is provided by means of a percentage differential characteristic. The relay operates in half a cycle during internal faults. In order to achieve sensitive ground-fault protection, separate primary and secondary ground-fault protection are provided. The relay algorithm is implemented on a single TMS320 digital signal processor and tested in real time using a three-phase laboratory power transformer 相似文献
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Transformer Differential and overcurrent schemes are traditionally used as main and backup protection respectively.
The differential protection relay (SEL487E) has dedicated harmonic restraint function which blocks the relay tripping
during the transformer magnetizing inrush conditions. However, the backup overcurrent relay (SEL751A) applied to
the transformer protection does not have harmonic restraint element and trip the overcurrent relay during the inrush
conditions. Therefore, major contribution of this research work is the developed harmonic blocking scheme for
transformer which uses element (87HB) of the transformer differential relay (SEL487E) to send an IEC61850 GOOSE-based
harmonic blocking signal to the backup overcurrent relay (SEL751A) to inhibit from tripping during the transformer
magnetizing inrush current conditions. The simulation results proved that IEC61850 standard-based protection scheme is
faster than the hardwired signals. Therefore, the speed and reliability of the transformer scheme are improved using the
IEC61850 standard-based GOOSE applications. 相似文献
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三相变压器励磁涌流及保护方案 总被引:6,自引:2,他引:4
针对近期基于波形对称原理的变压器差动保护频繁误动的现状,从三相变压器励磁涌流的产生机理入手,分析了波形对称原理与2次谐波制动原理的内在联系,结合目前流行的2种相位补偿方式,指出了传统采用相间差动的保护方案误动的根本原因.针对220 kV以上D侧套管内装设电流互感器的变压器,提出了一种采用相电流差动接线的保护方案.该方案在理论上克服了传统方案的全部弊端,并可实现真正的分相制动;缺点在于保护范围有所减小,需要其他保护来配合. 相似文献
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一起特高压变压器的差动保护误动分析及防范措施 总被引:3,自引:0,他引:3
通过建立MATLAB仿真模型,分析了在特高压交流试验示范工程投运调试过程中出现的一起由于中压侧空投主变压器产生励磁涌流而导致调压变压器差动保护误动作的案例。针对特高压变压器结构上的特殊性,分析了合闸角、剩磁等因素对励磁涌流的影响,仿真复现了现场故障录波波形。针对调压变压器差动电流中二次谐波含量较低可能引起的误动,从2个方面提出了相应的解决方案:指出二次谐波涌流闭锁判据宜采用三取二闭锁方式,但在某些特殊情况下,依然可能失效,进而提出了利用二次谐波变化趋势来识别励磁涌流和故障电流的辅助判据,并对综合判据进行了仿真验证;分析了调压变压器容量对励磁涌流的影响,提出在条件允许的情况下,适当增加调压变压器容量来避免励磁涌流可能引起的误动,为提高调压变压器差动保护可靠性提供了新思路。 相似文献