电弧炉谐波注入对电力系统的影响分析

发布时间：2018-02-09 19:54

  本文关键词： 交流电弧炉 电弧模型 背景谐波 谐波分析　出处：《东南大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着世界经济和科技的发展,非线性负荷的数量、种类和用电量与日俱增。这些非线性负荷不可避免地会产生谐波,导致电网电压畸变率的上升,对输电线路、电气设备、通讯设备造成不利影响,甚至会引起电力设备损坏和电网安全事故。因此,对电力系统谐波进行研究是非常紧迫和有必要的。近年来,在炼钢业和冶炼技术飞速发展的同时,越来越多的电弧炉设备被应用于金属冶炼行业,其容量也越来越大,逐渐成为电网中一种重要的谐波源,所以,对电弧炉谐波进行分析和研究具有很大的实际意义。在分析电弧炉之前,应该充分了解它的工作原理和特点,并建立起合适的理论模型。本文首先简述了电弧炉的发展过程,结合其炼钢原理分析了熔化期、氧化期和还原期的工作特点,阐述了它给电力系统带来的谐波、电压闪变、三相不平衡、功率因数低、影响电气设备正常工作等问题,并针对电弧炉谐波问题简单介绍了目前常用的几种谐波分析方法。在上述工作的基础上,详细分析了电弧炉交流电弧的物理特性和其电气系统各模块的简化等效电路,推导了交流电弧相应的电阻性模型及其电气系统的状态方程,最后针对交流电弧电阻模型的各个参数,给出了可行的估算方法。接着,论文从两个方面开展研究了电弧炉建模及其对电网影响的研究。论文建立了一种交流电弧炉时域等效电压源模型,先基于分段线性化的方法对电弧炉V-Ⅰ特性曲线进行线性化,考虑电弧炉实时有功,可以推导出电弧炉的静态模型,适用于电弧炉谐波分析；在电弧炉电阻的静态模型上,叠加正弦信号或白噪声随机信号,可以推导出适用于电压波动和闪变研究的,反映电弧炉动态特性的动态模型。基于PSCAD完成了模型搭建,仿真结果符合实际测量的电弧电压动态特性,从而证明了该模型的准确性。论文建立了考虑背景谐波的含电弧炉电力系统模型,进行谐波分析。采用PSCAD自带电弧炉和基于谐波电流源的电弧炉两种建模方法,基于某炼钢厂实测数据,仿真获得背景谐波电源出口处电压和电弧炉接入点电压,对这两点的电压进行三相傅里叶分解,从而进行谐波分析。通过仿真结果可以得出：电弧炉谐波注入会导致电网电压发生畸变,而且这种畸变通常是三相不对称的。
[Abstract]:With the development of the world economy and science and technology, the number, variety and power consumption of nonlinear loads are increasing. These nonlinear loads will inevitably produce harmonics, which will lead to the rise of the voltage distortion rate of the power network, and to the transmission lines, electrical equipment, Communication equipment causes adverse effects, and even causes power equipment damage and power network safety accidents. Therefore, it is very urgent and necessary to study the harmonic of power system. In recent years, with the rapid development of steelmaking and smelting technology, More and more electric arc furnace equipments are used in the metal smelting industry, and their capacity is becoming more and more large, which gradually becomes an important harmonic source in the power grid, so, It is of great practical significance to analyze and study the harmonics of the EAF. Before analyzing the EAF, it is necessary to fully understand its working principle and characteristics, and to establish a suitable theoretical model. Firstly, the development process of EAF is briefly described in this paper. Based on its steelmaking principle, the working characteristics of melting, oxidation and reduction periods are analyzed, and the problems such as harmonics, voltage flicker, three-phase imbalance, low power factor and influence on the normal operation of electrical equipment are expounded. Based on the above work, the physical characteristics of AC arc of arc furnace and the simplified equivalent circuit of each module of electric system are analyzed in detail. The resistance model of AC arc and the state equation of electrical system are derived. At last, a feasible estimation method for each parameter of AC arc resistance model is given. In this paper, the modeling of arc furnace and its influence on power network are studied from two aspects. A time-domain equivalent voltage source model of AC arc furnace is established. Firstly, the V- 鈪，

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