高频谐波导致谐振过电压的分析与抑制  

Analysis and Suppression of Resonance Over-voltage Induced by High Frequency Harmonics

作　　者：黄友聪[1] 周凯[1] 牟秋谷[1] 赵威[1] 

机构地区：[1]四川大学,电气信息学院,四川成都610065

出　　处：《电力电子技术》2013年第2期95-97,共3页Power Electronics

摘　　要：变频调速牵引系统向电网注入大量高频谐波,容易诱发谐振过电压,使电力设备损坏。使用阻抗扫描法和频谱分析法分析了某条电力机车牵引试验线路过电压事故,并提出一种有效且经济的解决措施。首先使用电能质量测试仪和高速示波器测量接触网上的谐波和过压波形;然后建立牵引供电系统谐振模型,绘出系统阻抗扫描图,计算系统自振荡频率为3.9 kHz与变流器高频特征谐波构成谐振回路,与测试数据相吻合;最后通过改变牵引变压器绕组接线方式,减少电源阻抗,增加系统稳定性同时破坏谐振条件。现场测试表明,谐波减轻、谐振过电压消失,接触网电压有效值从原来的28.26 kV降至25.5 kV,证明了该方法有效。A large number of high frequency harmonics of VVVF traction system are injected in the grid.It is likely to cause resonance over-voltage and damage to electrical equipment.An over-vohage accident is analyzed in an elec- tric locomotive traction experimental line used impedance scanning and spectrum analysis methods.An effective and economic measure to solve the resonance over-voltage is proposed.Firstly,power quality measurement and high-speed oscilloscope are used to measure the catenaries＇ harmonic and over-voltage waveform.To depict system impedance scanning graph, a resonance model of the traction power supply system is created.The system of 3.9 kHz self oscilla- tion frequency constitutes a resonance circuit with high frequency characteristic harmonics of converter, that conforms to measured data.Finally, the trac-tion transformer winding wring is changed, in order to reduce the source impedance. This method undermines the reso-nance condition while increasing the stability of the system.The field tests indicate that the harmonic reduces,the resonance over-voltage disappeares and the catenaries＇ voltage falls from original 28.26 kV to 25.5 kV.So the method is proved effectively.

关 键 词：电能质量 牵引供电 高频谐波 谐振过电压 

分 类 号：TM7[电气工程—电力系统及自动化]