一种变压器短路试验供电装置网侧电流平衡控制研究  

Research on Current Balance Control of Grid Side for a Transformer Short Circuit Test Power Supply Device

作　　者：王康 王国彬 曾静岚 刘冰 赵晓君[2] 黄孟欣 WANG Kang;WANG Guobin;ZENG Jinglan;LIU Bing;ZHAO Xiaojun;HUANG Mengxin(State Grid Fujian Electric Power Research Institution,Fuzhou 350007,Fujian,China;School of Electrical Engineering,Yanshan University,Qinhuangdao 066000,Hebei,China;Beijing SG-EPRI UHV Transmission Technology Co.,Ltd.,Beijing 102200,China)

机构地区：[1]国网福建省电力有限公司电力科学研究院,福建福州350007 [2]燕山大学电气工程学院,河北秦皇岛066000 [3]北京国网普瑞特高压输电技术有限公司,北京102200

出　　处：《电气传动》2021年第10期30-37,61,共9页Electric Drive

摘　　要：当利用电网进行变压器短路试验时,较大的短路电流会对电网产生冲击,影响同一电网中其他负荷的安全运行。为此,设计了一种三相四线制变压器短路试验供电装置,通过位于直流母线上的储能装置,额外形成一条能量供给通道,以减轻短路电流对电网的冲击。然而利用该供电装置对单相变压器进行短路试验时,若不加以有效控制,系统输出侧的不平衡电流将导致网侧电流同样出现不平衡现象,从而造成网侧中点电位发生偏移,不仅影响装置控制精度和效果,还会使其三相输出电压不对称,严重时会造成被测变压器的损坏。为此,提出了一种基于基波功率平衡的输入电流补偿算法,用于计算输入电流基准,实现不平衡变压器短路试验条件下的网侧三相电流平衡运行,并通过实验验证了该算法的可行性和有效性。When the transformer short-circuit test is carried out in the power grid,the larger short-circuit currents will have a significant impact on the power grid and affect the safe operation of other loads in the same power grid.For this reason,a power supply device for the transformer short-circuit test was designed in the threephase four-wire systems,which could form an additional energy supply path through the energy storage devices located on the DC bus to reduce the impact of short-circuit currents on the power grid.However,when this power supply device was used to perform a short-circuit test for a single-phase transformer,if it was not effectively controlled,the unbalanced currents on the output side of the system would also lead to the unbalance currents on the grid side,resulting in the offset of the midpoint potential on the grid side,which not only could affect the control accuracy and effect of the device,but also make the three-phase output voltage asymmetrical.In serious cases,it might cause damage to the tested transformer.To this end,an input current compensation algorithm based on fundamental power balance was proposed to calculate the input current references,so as to realize the balanced operation of three-phase currents on the grid side under the condition of the short-circuit test for unbalanced transformers.Also,the feasibility and effectiveness of the algorithm were verified by experiments.

关 键 词：变压器短路试验 功率平衡 不平衡电流控制 直流母线电压波动 

分 类 号：TM761[电气工程—电力系统及自动化]