New Method for Backup Protection in Distribution Networks With DG Based on Idea of Action Time Limit Curve Fitting
The integration of distributed generation(DG)may alter the short-circuit current characteristics of the power system,thereby affecting the selectivity and coordination of the inverse time overcurrent protection.Therefore,this article proposes a new method for backup protection in distribution networks with DG based on the idea of action time limit curve fitting.Starting from the action time difference between the main protection and the backup protection in the distribution network,a curve fitting model is established,and the gradient descent method is used to optimize the action time curve of the inverse time overcurrent protection.By considering the selectivity of the protection and the impact of DG connection in the optimization setting calculation,the optimization parameters are applied to every segment position in the distribution network.Then,by setting some two-phase and three-phase short-circuit faults in the distribution network,the parameters are adjusted based on the fault locations and types,and ultimately obtaining the global optimal solution of the parameters.Based on the PSCAD/EMTDC simulation software,simulation analysis is conducted to verify the effectiveness and practicality of the proposed method.
inverse time overcurrent protectiondistributed generationgradient descent algorithmcurve fittingrapidityselectivity
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