电力变压器励磁涌流识别新方法研究

发布时间：2018-01-17 21:30

本文关键词：电力变压器励磁涌流识别新方法研究　出处：《华北电力大学》2014年硕士论文　论文类型：学位论文

【摘要】：如何防止变压器励磁涌流导致的差动保护误动作和提高空投于故障变压器(特别是匝间短路)时保护的灵敏度是变压器差动保护先天性的、不可回避的难题。论文针对该问题展开工作,提出了相应的解决措施,研究的主要内容和成果有：提出了一种利用波形奇异因子辨别变压器内部故障和励磁涌流的新方法。首先定义了波形奇异因子及其计算方法,并揭示了励磁涌流和内部故障情况下,波形奇异因子不同的变化趋势。在此基础上,给出了励磁涌流和内部故障识别判据。动模试验验证结果表明,即使是发生小匝比匝间故障的情况下,该方法也能快速、准确、可靠的区分内部故障与励磁涌流,计算量小,易于工程实现。提出了一种基于正弦波相似因子识别变压器励磁涌流和内部故障电流的新方法。首先给出了正弦波相似因子的定义及其计算方法,然后根据正弦波相似因子在励磁涌流和故障电流情况下不同的变化趋势,提出了新的识别判据。动模试验结果表明,励磁涌流的正弦波相似因子维持在很小的数值,而故障电流的正弦波相似因子则有明显的变化,该方法能够快速切除变压器内部故障,识别灵敏度高,计算简单,易于实施。提出了一种利用标准化漏电感识别励磁涌流和故障电流的新方法。该方法利用正常条件下变压器的电阻和漏感参数,通过差分方程递推变压器空载合闸时的漏感值,在此基础上标准化漏电感参数,以使保护装置参数设置更具普遍性。动模试验结果表明,该方法不受变电站中变压器母线侧TV安装位置影响,并可确保内部故障时变压器能够被可靠地快速切除,且该方法对轻微故障具有足够的灵敏度。
[Abstract]:How to prevent the maloperation of differential protection caused by inrush current of transformer excitation and how to improve the sensitivity of protection when the fault transformer (especially the inter-turn short circuit) is dropped by air is congenital of transformer differential protection. The paper works on this problem and puts forward the corresponding solutions. The main contents and results of the study are as follows: A new method for distinguishing internal faults and inrush currents of transformers by waveform singularity factor is proposed. Firstly, the waveform singularity factor and its calculation method are defined, and the excitation inrush current and internal faults are revealed. On the basis of this, the inrush current and internal fault identification criteria are given. The results of dynamic simulation test show that even in the case of small turn ratio inter-turn fault. This method can also be used to distinguish internal faults from excitation inrush currents quickly, accurately and reliably, and it is easy to be realized in engineering. A new method for identifying inrush current and internal fault current of transformer based on sinusoidal similarity factor is proposed. Firstly, the definition of sinusoidal similarity factor and its calculation method are given. Then according to the different trends of sinusoidal wave similarity factor under excitation inrush current and fault current, a new identification criterion is proposed. The sinusoidal wave similarity factor of excitation inrush current is maintained at a very small value while the sinusoidal wave similarity factor of fault current has obvious changes. This method can quickly remove the internal fault of transformer and has high sensitivity. The calculation is simple and easy to implement. A new method for identifying inrush current and fault current by using standardized leakage inductance is presented, which utilizes the resistance and leakage inductance parameters of transformer under normal conditions. Through the difference equation recursion transformer leakage inductance value when no load switch, on this basis standardization leakage inductance parameter, in order to make the protection device parameter set more universal. The dynamic simulation test results show. This method is independent of the transformer busbar side TV installation position in the substation, and can ensure that the transformer can be removed reliably and quickly in case of internal fault, and the method has sufficient sensitivity for minor faults.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM41

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