配电网接地故障辨识与消弧柜投入控制研究

发布时间：2018-04-02 16:36

本文选题：配电网　切入点：消弧柜　出处：《长沙理工大学》2014年硕士论文

【摘要】：线路接地故障和变压器内部接地故障辨识问题是经消弧柜接地配电网亟待解决的一大难题。经消弧柜接地配电网采用中性点不接地的方式,不需使用消弧线圈,当线路发生单相接地故障时,将安装在母线处的消弧柜合闸,解决了弧光接地故障带来的危害。但同时也带来了变压器内部故障时消弧柜误动而使变压器内部绕组短路的威胁。因此如何辨识线路故障和变压器故障并使消弧柜正确动作是维护电网安全稳定运行的重要研究内容。为此,论文旨在发现现有辨识方法存在的不足,研究新的辨识方法,提出了基于多信息融合的故障辨识方法以及消弧柜动作后的故障二次辨识方法,并对消弧柜进行相应的投入控制。为解决经消弧柜接地配电网线路故障和变压器故障的辨识难题,论文分析了上述两种故障情况下变压器出口和各线路首端零序电流和负序电流大小、相位等故障信息,计算了各条线路首端与变压器出口的序电流比值,分别构建了基于零序电流标幺值的辨识判据和基于负序电流标幺值的辨识判据,分别提出了基于零序电流和负序电流的故障辨识方法；并根据序电流的相位差别构建了基于序电流相位的辨识判据,提出了基于序电流相位的故障辨识方法。为充分挖掘故障信息,全面刻画故障状态,论文分析在线路故障和变压器内部故障情况下监测出口零序电流和零序电压导数之间的关系,提出了基于相关分析的故障辨识方法。比较论文提出的四种辨识方法的优缺点及适用范围,构建基于多判据的信息融合辨识判据,提出了基于多信息融合的故障辨识方法,并根据辨识结果对消弧柜进行相应的投入控制。该辨识方法不受系统运行方式及参数的影响,可靠性高针对特定情况下辨识错误而消弧柜误动的情况,通过检测消弧柜动作后流经消弧柜的电流的大小来重新辨识故障,提出了消弧柜动作后的故障二次辨识方法和消弧柜投入控制策略,避免了消弧柜误动而引发变压器内部绕组短路而使变压器烧毁等严重事故。通过MATLA和EMTP仿真验证,上述故障辨识方法能对经消弧柜接地配电网中的线路故障和变压器故障进行准确辨识,并对消弧柜进行相应投入控制,实现了变压器绕组100%的保护,避免了变压器内部故障时消弧柜误动作引起变压器烧坏等事故的发生,辨识精度和可靠性高,有待在经消弧柜接地配电网中推广应用。
[Abstract]:The identification of line grounding fault and transformer internal grounding fault is a difficult problem to be solved urgently in the grounding distribution network through the arc-suppression cabinet.When the single phase grounding fault occurs, the arc-suppression cabinet will be installed in the busbar to close the arc-suppression cabinet, which solves the harm caused by the arc-light grounding fault.But at the same time, it also brings about the threat of short-circuit in transformer inner windings because of the maloperation of arc-suppression cabinet.Therefore, how to identify line faults and transformer faults and make the arc-suppression cabinet operate correctly is an important research content to maintain the safe and stable operation of power grid.Therefore, the purpose of this paper is to find out the shortcomings of the existing identification methods, to study new identification methods, and to propose a fault identification method based on multi-information fusion and a secondary fault identification method after the operation of the silencer.And the corresponding input control to the arc suppression cabinet.In order to solve the problem of fault identification of distribution network line and transformer fault through arc-suppression cabinet, the fault information of zero sequence current and negative sequence current at the outlet of transformer and the first end of each line are analyzed in this paper, such as the magnitude and phase of the zero sequence current and negative sequence current at the first end of each line.The sequence current ratio between the first end of each line and the outlet of the transformer is calculated, and the identification criteria based on the zero sequence current standard and the negative sequence current standard unitary value are constructed, respectively.The fault identification method based on zero sequence current and negative sequence current is proposed, and the identification criterion based on sequence current phase is constructed according to the phase difference of sequence current, and the fault identification method based on sequence current phase is proposed.In order to fully mine fault information and depict the fault state, the relationship between zero-sequence current and zero-sequence voltage derivative is analyzed in this paper, and a fault identification method based on correlation analysis is proposed.By comparing the advantages and disadvantages of the four identification methods proposed in this paper, the information fusion identification criterion based on multi-criteria is constructed, and the fault identification method based on multi-information fusion is proposed.According to the identification results, the corresponding input control of the arc suppression cabinet is carried out.The identification method is not affected by the operation mode and parameters of the system, and the fault is identified by detecting the magnitude of the current flowing through the silencer by detecting the magnitude of the current flowing through the silencer after the operation of the silencer.The second identification method of the fault after the operation of the silencer and the input control strategy of the silencer are put forward to avoid serious accidents such as fault operation of the silencing cabinet and short circuit of the inner winding of the transformer and the burning of the transformer.The simulation results of MATLA and EMTP show that the above fault identification method can accurately identify the line faults and transformer faults in the grounding distribution network through the arc-suppression cabinet, and the corresponding input control of the arc-suppression cabinet can realize 100% protection of the transformer windings.It can avoid accidents such as burning out of transformer caused by maloperation of arc suppression cabinet inside fault of transformer, and has high identification precision and reliability. It needs to be popularized and applied in distribution network through arc-suppression cabinet grounding.
【学位授予单位】：长沙理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM862

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