Overcurrent relay coordination in the presence of the uncertainties of production and consumption

Uncertainties in power distribution systems are a major challenge today. With the high penetration of distributed energy resources, great uncertainties have arisen, and thus difficulties in decision-making in such systems have occurred. In this paper, the uncertainties of production and consumption and their impact on the coordination of relay protection are presented. A new calculation of the coordination of overcurrent protection is presented, considering the uncertainties of production and consumption modeled by interval arithmetic. In the optimization model of relay protection coordination, the approach for uncertainty modeling using intervals is applied. The results of the proposed calculation are confirmed by test examples. In addition to the proposed analytical approach, the paper also presents an approach with Monte Carlo simulations. The paper demonstrates that it is necessary to consider the uncertainties of production and consumption in the calculation of overcurrent protection coordination in order to preserve the selectivity of protection.