operation characteristics and fault characteristics have been changed by the access of distributed generation. Because the traditional current protection scheme of distribution network does not take into account the synergistic response and output fluctuation characteristics of distributed generator
this leads to a decrease in the sensitivity of the protection and may cause the protection to lose selectivity. To address this problem
an improved current protection scheme for distribution networks with inverter-interfaced distributed generators (IIDGs) is proposed
based on the IIDG output fluctuation. The scheme can iteratively calculate the short circuit current under normal operation
adjust the setting values of phases Ⅱ and Ⅲ of upstream line current protection and phase I of the downstream line current protection in real time
and solve the IIDG output range applicable to the setting
to ensure that the downstream line operates correctly when the new energy output fluctuates. Finally
it has been confirmed that the proposed scheme significantly enhances the sensitivity of phases Ⅱ and Ⅲ of upstream protection of the IIDG access points by Matlab programming and PSCAD/EMTDC simulations. Additionally
it ensures the selectivity of phase I of downstream protection
thereby improving the effectiveness of stepped current protection.
The College of Electrical and Information Engineering, Lanzhou University of Technology
School of Control and Computer Engineering, North China Electric Power University
Department of Electrical Engineering, Tsinghua University
School of Mechanical and Power Engineering, Jiangsu Organic Solid Waste Deep Disposal and Hydrogen Production Engineering Research Center,Jiangsu Key Laboratory of Process Enhancement and New Energy Equipment Technology, Nanjing Tech University
College of Energy and Mechanical Engineering, Shanghai University of Electric Power