Research on unloaded transformer controlled switching considering residual flux
DOI：10.7667/PSPC171756
Key Words:inrush current  residual flux  controlled switching technology  unloaded transformer  gang-operated breaker
Author NameAffiliationE-mail
CHEN Chuanjiang School of Electrical Engineering and Electronic Information, Xihua University, Chengdu 610039, China  
FANG Chunen School of Electrical Engineering and Electronic Information, Xihua University, Chengdu 610039, China
Sichuan Province Key Laboratory of Power Electronics Energy-saving Technologies & Equipment, Chengdu 610039, China 		fangchunen@163.com 
ZENG Junlong School of Electrical Engineering and Electronic Information, Xihua University, Chengdu 610039, China  
LI Wei School of Electrical Engineering and Electronic Information, Xihua University, Chengdu 610039, China
Sichuan Province Key Laboratory of Power Electronics Energy-saving Technologies & Equipment, Chengdu 610039, China 		 
LUO Yan School of Electrical Engineering and Electronic Information, Xihua University, Chengdu 610039, China
Sichuan Province Key Laboratory of Power Electronics Energy-saving Technologies & Equipment, Chengdu 610039, China 		 
REN Xiao School of Electrical Engineering and Electronic Information, Xihua University, Chengdu 610039, China
Sichuan Province Key Laboratory of Power Electronics Energy-saving Technologies & Equipment, Chengdu 610039, China 		 
Hits: 3330
Download times: 1319
Abstract:Random energization of unloaded transformers may generate inrush currents, which easily causes protective relay mis-operation, imposes sever mechanical stresses on the transformer windings and reduces power quality of the system. Controlled switching technology is used for suppressing these inrush currents. The key to realize controlled switching is the effective estimation of the residual flux in transformer core after a transformer de-energization. Based on the analysis of the theories of controlled switching unloaded power transformer, a method of measuring the residual flux based on numerical integration is proposed. Energization of unloaded transformers is simulated with PSCAD/EMTDC, and simulation results validate the effectiveness of the controlled switching technology. Unloaded transformer controlled switching test platform is built, and the tests of random and controlled switching are conducted. The experimental results indicate that the controlled switching considering residual flux is effective in suppressing the inrush current compared with random switching, and validate the effectiveness of residual flux measurement method. Finally, the suitable controlled switching strategy of unloaded transformer with gang-operated breaker is proposed, and simulation results validate its effectiveness. This work is supported by National Natural Science Foundation of China (No. 51477142), Sichuan Provincial Department of Education Project (No. 12ZB131 and No. 14ZB0123), and Innovation Fund of Postgraduate of Xihua University (No. ycjj2017060).
View Full Text  View/Add Comment  Download reader