Power flow optimization for DC distribution grid with distributed energy access based on Newton–Raphson method through upper level control

Abstract

DC distribution grids with distributed energy integration have been gaining a continually increasing interest in recent years both in academia and industry, power flow of the grids is a key issue to make use of these energy effectively and reliably, paper aims at optimizing the power flow of DC distribution through the upper level control, by considering the factors of distributed energy permeability and DC grid topology, without hardware investment increase nor using complex algorithm. firstly, the change rule of the network loss and voltage distribution are studied under different distributed energy permeability values and DC grid topology, Secondly, one OPF mathematical model of DC distribution network is established taking the index of network loss and voltage imbalance degree as objective function. According to the change of system flow, the optimized instruction value is provided by the system through calculation for each AC/DC, DC/DC converter; an optimization method of DC power flow is presented by controlling converter instruction. At last, two typical cases are demonstrated by simulation of PSCAD/EMTDC, indexes of the network loss and voltage imbalance degree of the DC distribution network are compared before and after the optimization, Simulation results show that the presented method is feasible to promote DC Distribution Grid.