Research on Adaptive Current Control Method in Circuit Breaker Protection Characteristic Test
You Yingmin1,2, Wang Jingqin1, Shu Liang2, Zhang Haigen2, Chen Chong2
1. State Key Laboratory for Reliability and Intelligence of Electrical Equipment Hebei University of Technology Tianjin 300130 China; 2. Yueqing Institute of Industry Wenzhou University Wenzhou 325000 China
Abstract：Current converter is the core device to test the protection characteristics of circuit breaker. The existing test methods lack power factor adjustment. The current accuracy and stability also need to be improved. An adaptive control strategy for the circuit breaker testing application is proposed, in which a two-stage dual closed-loop control method is presented based on the front-stage fuzzy control and the post-stage impedance compensation. For the front-stage power factor compensation unit, the tracking error is introduced into the Sugeno-type fuzzy control to compensate the front-stage DC voltage tracking. At the post stage, a discrete impedance integration method is used to adaptively calculate the load impedance and an impedance compensation is then performed to improve current accuracy. The power factor correction and current accuracy are compared via both simulation and experiments. Comparison results show that compared with conventional method, the proposed strategy is able to reduce the current error from 3% to 1.2%. The maximum reduction ratio of THD is up to 17.1 %, which is significant to reduce the current distortion and grid harmonics.
2020, Vol. 35 
