Optimal Power Flow in Distribution Networks with High Penetration of Photovoltaic Units

Recently, the integration of distributed generation (DG) into distribution networks has grown significantly. As a result of this integration, optimal power flow (OPF) can be applied to the distribution network as an effective tool in order to enhance the control, operation and planning in the distribution grid. The nonlinearity of OPF problem in distribution networks requires the application of nonlinear optimization methods. This paper investigates how high penetration photovoltaic (PV) units impact the voltage regulation and power flow in active distribution networks. A multi-objective function is used to define the nonlinear power flow problem and Cuckoo Search (CS) algorithm is applied to solve the OPF problem. The proposed method was tested by using IEEE 123 nodes test case. Comparing the results of the PV unit with the traditional operation methods shows that locating PV units in the unbalanced distribution system would lead to better performance.