变压器励磁涌流抑制技术研究

发布时间：2018-06-19 00:06

本文选题：变压器 + 励磁涌流　；参考：《山东大学》2017年硕士论文

【摘要】：变压器是连接电网与用户的枢纽,在电力系统中不可或缺,其承载着电压的升降,运行状态影响系统的电能质量。虽然经过长期的使用和不断的改进,但变压器的合闸稳定性和运行安全性始终未达到最佳。空载合闸时,因为投入时刻的随机性和铁磁材料的非线性,往往使变压器的工作区处于饱和区,工作点超过膝点,磁化电流迅速增大,称其为励磁涌流。励磁涌流会破坏变压器的相关保护,使变压器运行异常,无法正常合闸。较大的励磁涌流还会对断路器以及变压器的绕组造成损害,对电网造成污染,因而抑制变压器空载合闸时的励磁涌流显得尤为重要。本文查阅了这几年的国内外文献,由产生的机理认识励磁涌流,由危害阐述抑制励磁涌流的必要性,在搜集前人工作的基础上总结励磁涌流的识别技术和抑制技术。目前励磁涌流的识别技术应用普遍,易于保护配合,但抑制技术能从基础上真正消除励磁涌流。励磁涌流抑制技术有很多,通过对比可知选相合闸技术抑制效果明显,比较容易实现,选相合闸技术成为本文研究的重点。为分析变压器空载合闸时的励磁涌流,认识合闸的动态过程,本文对变压器磁通进行推导,并使用MATLAB工具对单相变压器的励磁涌流进行模拟。通过观察电流的波形,归纳其特点和影响参数,为下一步工作做准备。对三相变压器应用不同策略下的选相合闸技术,并使用MATLAB软件进行仿真,最终确定了同步合闸策略下的选相合闸技术适用于三相变压器,分析磁通的变化情况,可以得知三相变压器选择剩磁无变化时的相角进行合闸基本上达到消除励磁涌流目的,具有不错的效果。对剩磁运用电压积分法进行估算,并使用MATLAB仿真三相变压器分闸时刻的截流和暂态恢复电压。本文设计了以同步合闸下的选相合闸技术为理论根基,以TMS320F2812为执行核心的变压器空载合闸励磁涌流抑制系统。抑制系统分为硬件电路和软件程序两个方面,硬件电路实现信号的采集和执行,软件程序实现数据的记忆和处理。通过多次实验,可知励磁涌流抑制系统能够实现其抑制功能,将励磁涌流的最大值降低至额定电流的3倍左右。
[Abstract]:Transformer is the hub connecting the power network with the users. It is indispensable in the power system. It carries the rise and fall of the voltage, and the running state affects the power quality of the system. Although the transformer has been used for a long time and improved continuously, the switching stability and operation safety of the transformer has never been optimal. Because of the randomness of the input time and the nonlinearity of ferromagnetic materials, the working area of the transformer is often in the saturation zone, the working point is above the knee point, and the magnetization current increases rapidly, which is called inrush current. The inrush current of excitation will destroy the protection of transformer, make the transformer abnormal operation and can not close normally. The larger inrush current will also cause damage to the circuit breaker and transformer windings and cause pollution to the power network, so it is very important to restrain the inrush current when the transformer is closed without load. In this paper, the domestic and foreign literatures in recent years are reviewed, the inrush current is recognized by the mechanism of generation, the necessity of restraining inrush current is expounded by harm, and the identification technology and suppression technology of inrush current are summarized on the basis of collecting the previous work. At present, the identification technology of inrush current is widely used, and it is easy to protect and cooperate, but the suppression technology can eliminate the inrush current on the basis of it. There are a lot of inrush current suppression techniques. Through comparison, it can be seen that the suppression effect of phase selection closing technology is obvious, and it is easy to realize. The phase selection and closing technology has become the focus of this paper. In order to analyze the inrush current of the transformer when it is closed without load and to understand the dynamic process of the closing, the magnetic flux of the transformer is deduced in this paper, and the inrush current of the single-phase transformer is simulated by MATLAB tool. By observing the waveform of the current, the characteristics and influence parameters are summarized to prepare for the next work. The phase selection and closing technology under different strategies is applied to the three-phase transformer, and the simulation is carried out with MATLAB software. Finally, the phase selection and closing technology under the synchronous closing strategy is determined to be suitable for the three-phase transformer, and the change of magnetic flux is analyzed. It can be known that the phase angle of the three-phase transformer with no change in remanence can basically eliminate the inrush current and has good effect. The remanent magnetism is estimated by voltage integration method, and the current closure and transient recovery voltage of three-phase transformer are simulated by MATLAB. In this paper, a transformer no-load switching inrush current suppression system is designed, which is based on the technology of phase selection and closing under synchronous closing, and uses TMS320F2812 as the executive core. The suppression system is divided into hardware circuit and software program. The hardware circuit realizes the signal acquisition and execution, and the software program realizes the data memory and processing. Through many experiments, it can be seen that the inrush current suppression system can achieve its suppression function and reduce the maximum value of inrush current to about 3 times of the rated current.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM41

【参考文献】