配电变压器三相不平衡的检测与分析

发布时间：2018-10-08 12:46

【摘要】：电能在社会经济发展和人们日常生活当中发挥着至关重要的作用,同时也是推动国家工业发达、科技进步和社会稳定的强大动力。随着科学技术和国民经济的不断进步,各式各样的负载在电网中不断出现,与此同时,人们对电能质量的重视程度也越来越高。电能的质量,普遍用供电电压的频率、偏移、波动、闪变、间断、塌陷、尖峰、谐波、畸变、三相不平衡和高频干扰等指标来表示,其中三相不平衡属于电能质量的重要指标之一。因为低压负荷广泛采取三相四线制接线,再加上单相负荷用电的随机性,所以导致配电变压器的三相负荷长期工作在不平衡状态。这就会引起诸如三相电压不平衡、零序电流过大、配电变压器设备局部发热等一系列问题,进而减少电动机有功输出、限制变压器的出力、加重配电线路的损耗,严重时,甚至还会烧断零线,并损坏用户的用电设备。电能质量对于电网和电器设备的安全、经济运行,对于保证企业的生产质量和人民生活的正常秩序都有十分重要的意义。本课题针对河南省焦作市配电变压器三相不平衡较为普遍的问题,深入探讨配电变压器三相不平衡的原因和危害,总结三相不平衡度的计算方法。设计电能质量检测装置,并进行实地调研和检测,选择工业区、居民区、商业区、城乡结合部内等30个点配电变压器为检测对象,得到大量现场测试数据。编写LabVIEW数据采集和分析软件,深入研究配电变压器三相不平衡的情况和负荷特征。采用MATLAB对低压负荷进行建立仿真模型,将仿真分析结果与现场测试数据的分析结果相对应,找到河南省焦作市配电变压器三相不平衡问题特征和原因,最后分别从管理和技术方面,给出治理配电变压器三相不平衡的方法和措施。
[Abstract]:Electric energy plays a vital role in the development of social economy and people's daily life, and it is also a powerful driving force to promote the development of industry, the progress of science and technology and the stability of society. With the development of science and technology and national economy, all kinds of loads appear in the power grid. At the same time, people pay more and more attention to the power quality. The quality of electrical energy is generally expressed by the frequency, deviation, fluctuation, flicker, discontinuity, collapse, peak, harmonic, distortion, three-phase imbalance and high-frequency interference of the supply voltage. Three-phase imbalance is one of the important indexes of power quality. The three-phase four-wire connection is widely used in low-voltage load and the randomness of single-phase load, so the three-phase load of distribution transformer works in unbalanced state for a long time. This will lead to a series of problems such as unbalance of three-phase voltage, excessive zero-sequence current, local heating of distribution transformer equipment, and so on, thereby reducing the active power output of the motor, limiting the output of the transformer, increasing the loss of the distribution line, and when serious, It can even burn off zero lines and damage users' electrical equipment. The power quality is of great significance to the safety and economic operation of the power grid and electrical equipment, and to the guarantee of the production quality of the enterprise and the normal order of the people's life. Aiming at the common problem of three-phase unbalance of distribution transformer in Jiaozuo City, Henan Province, the cause and harm of three-phase unbalance of distribution transformer are discussed in depth, and the calculation method of three-phase unbalance degree is summarized. A power quality testing device is designed, and a lot of field test data are obtained by selecting 30 distribution transformers in industrial area, residential area, commercial district and urban and rural joint area. The software of LabVIEW data acquisition and analysis is written to study the unbalance and load characteristics of distribution transformer. The simulation model of low voltage load is established by using MATLAB. The results of simulation analysis correspond to the analysis results of field test data, and the characteristics and causes of three-phase imbalance problem of distribution transformer in Jiaozuo City, Henan Province are found out. Finally, from the aspects of management and technology, the methods and measures of controlling the three-phase imbalance of distribution transformer are given.
【学位授予单位】：郑州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM421

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