变压器差动保护的研究与改进

发布时间：2018-01-17 01:35

本文关键词：变压器差动保护的研究与改进　出处：《华北电力大学》2014年硕士论文　论文类型：学位论文

【摘要】：随着我国电力的不断发展与进步,特高压输电线路的不断建设、超大容量机组不断增加、区域之间的电网互联的时代已经逐步实现,目前电网的复杂度也逐步加深,并且规模不断扩大,对电力系统的安全运行提出了新的要求。变压器作为电力系统中最重要的电气设备之一,在电网中承载着电力搬运工的角色,提高变压器保护的灵敏性与可靠性显得尤为重要。但是相对于母线等其它一次性设备而言,变压器保护的误动次数统计一直处于一个比较高的水平,并且随着电子式互感器在智能电站工程上的逐步使用,这给变压器保护带来了新的研究思路,特别是变压器差动保护的研究提出了新的方向。本文详细阐述了变压器差动保护的研究现状,对国内外的涌流识别的新原理、新方法进行了优缺点分析。理论分析了变压器励磁涌流、变压器恢复性涌流以及和应涌流形成的机理,做出了详细的理论推导,进一步详细分析了其影响因素。在理论分析的基础上采用MATLAB软件中Simulink模块对变压器的三种涌流分别进行了建模仿真。仿真结果展示了合闸角、线路故障切除对变压器励磁涌流的影响；而后,分析了变压器并联以及串联情况下和应涌流的形成过程并且得出系统电阻越大越容易造成变压器和应涌流的形成。通过以上分析发现必须采取一定的措施对变压器各种故障进行辨识以防止其保护误动而影响电力系统的稳定运行,接着介绍了EMD+TEO实现涌流与内部故障的辨别,进而实现涌流时闭锁差动保护,此种办法能够对变压器各种故障状态实现很好的辨识从而确保系统正常情况下的稳定运行。最后本文采用PSCAD软件构建了三绕组变压器电流差动保护仿真系统,并建立了变压器区内和区外故障仿真模型以及传统电流互感器和电子式电流互感器(ECT)仿真模型。通过对变压器区外、区内短路故障的仿真分析传统CT和ECT在传统比率制动特性的差动保护中的动作轨迹和动作出口。根据仿真结果,改进了传统变压器差动保护在ECT运用中整定原则和整定定值方案,在一定程度上解决了智能电站工程中变压器差动保护的整定问题。
[Abstract]:With the development and progress of our country ' s electric power , the construction of extra - high voltage transmission line , the increasing of super - large capacity unit , the time of grid interconnection between the regions has been gradually realized , and the complexity of the power grid is gradually deepened , and the scale is continuously expanding , and the new requirements for the safe operation of the power system are put forward . As one of the most important electrical equipment in power system , the transformer is the most important electrical equipment in power system . It is very important to improve the sensitivity and reliability of transformer protection . However , in the case of other disposable equipment such as bus and so on , the error number of transformer protection has always been at a relatively high level , and with the gradual use of electronic mutual inductor in the engineering of intelligent power station , this brings new research thinking to the protection of transformer , especially the research of transformer differential protection . In this paper , the current situation of transformer differential protection is described in detail , and the new principle and new method of inrush current identification at home and abroad are analyzed . Based on the theory analysis , the simulation results of three kinds of inrush current of transformer are simulated by Simulink module in MATLAB software . The simulation results show the influence of switching angle and line fault removal on the inrush current of transformer . In the end , the current differential protection simulation system of three - winding transformer is constructed by PSCAD software , and the simulation model of transformer area and outer fault is established , and the simulation model of traditional current transformer and electronic current transformer ( ECT ) is established . Through simulation analysis of the short - circuit fault in the area of transformer , the operation locus and action exit of traditional CT and ECT in the differential protection of traditional ratio braking characteristic are analyzed . According to the simulation results , the setting principle and setting value scheme of traditional transformer differential protection in ECT application are improved , and the setting problem of transformer differential protection in intelligent power station engineering is solved to some extent .

【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】：TM774

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