低频方波的变压器伏安特性曲线的试验和计算  

Test and Calculation Method for Volt-Ampere Characteristic Curve of Transformer Based on Low-Frequency Square-Wave Excitation

作　　者：杨宁 梁仕斌 刘涛 刘鑫 刘明 Yang Ning;Liang Shibin;Liu Tao;Liu Xin;LinMing(Postgraduate Workstation of Yunnan Power Grid Company,Kunming 650217;Yunnan Electric Power Test ＆ Research Institute,Kunming 650217;Yunnan Electric Power Technology Company,Kunming 650217)

机构地区：[1]云南电网有限责任公司研究生工作站,昆明650217 [2]云南电力试验研究院(集团)有限公司,昆明650217 [3]云南电力技术有限责任公司,昆明650217

出　　处：《云南电力技术》2018年第5期81-87,共7页Yunnan Electric Power

摘　　要：采用低频试验方法测量变压器伏安特性曲线可以降低电源容量及试验电压等级,但是现有的低频法需要采用变频正弦波电源作为试验电源,而大容量变频正弦波电源制造难度大、成本高,所以提出一种基于低频方波的变压器伏安特性曲线的试验和计算方法。该方法利用变频方波电源进行空载试验,对实测的励磁电压和励磁电流进行折算,按照从低频方波到同频率正弦波,再到工频正弦波的折算步骤,使得折算后的伏安特性曲线与工频正弦波激励下的结果有较好的一致性。并且在单相变压器上开展试验,10,15,20Hz的方波折算后的励磁电流与50Hz正弦波实测结果的相对误差小于6.6%,励磁电压相对误差小于0.32%。结果表明,本方法折算精度高,具有工程应用价值。Using low-frequency experimental method to measure volt-ampere of transformer can reduce the power capacity and testing voltage level. However, the existing low-frequency method needs a variable frequency sine-wave as the testing power supply. Considering the difculty and cost of large-capacity frequency conversion power of sine-wave, a low-frequency method for volt-ampere characteristic curve of transformer based on square-wave excitation is proposed. This method uses the variable frequency square-wave power supply to conduct the no-load test, then convert the measured excitation voltage, excitation current to industrial-frequency（IF）. In order to make the converted volt-ampere characteristic curve is essentially in consistent with that in IF, the conversion steps from the low-frequency square-wave to the sine-wave of same frequency, and then to the sine-wave in IF should be conducted. In addition, experiments were conducted on the single phase power transformer. Comparing conversion results which using 10,15,20Hz with directly measured results under IF, the relative error of excitation current and excitation voltage is below 6.6%, 0.32%, respectively. These results show that the method proposed in this paper possesses high conversion accuracy, which is valuable in the feld of engineering.

关 键 词：方波 变压器 伏安特性曲线 低频法 

分 类 号：TM74[电气工程—电力系统及自动化]