Investigation on Optimal Power Flow Calculation Method of Distribution Network Based on Convex Optimization

In order to improve the real-time performance of power system power flow calculation, the non-convex constraint in the optimal power flow problem is transformed into a convex function by introducing relaxed variables, and then the non-convex optimal power flow problem is transformed into a convex optimization problem. Considering the possible voltage overlimit caused by the large-scale access of distributed photovoltaic, the method of simultaneous regulation of capacitor and distributed photovoltaic is proposed, and then the convex optimal power flow method is used to solve. The network loss and computation time of the non-convex optimal power flow and the convex optimal power flow are compared for the IEEE33 system. Then, the voltage overlimit probability, mean voltage offset and network loss corresponding to the conventional method without reactive power optimization control, simultaneous regulation of capacitor and distributed photovoltaic method are compared. The results reveal that the convex optimal power flow calculation method is superior to the non-convex optimal power flow calculation method both in network loss and computation time. The method of simultaneous regulation of capacitor and distributed photovoltaic is superior to the conventional method without reactive power optimization according to voltage overlimit probability, mean voltage offset and network loss.