Impact of Realistic Voltage Dependent ZIP Load Modeling on Optimal Multi-PV Allocation and Reverse Power Flow Mitigation in Radial Distribution Networks

Abstract

In the DG integrated modern radial distribution network, for detailed analysis and optimal planning, load representation plays a crucial role. Unlike the traditional constant power load model, the actual distribution load exhibit strong voltage dependency, which can be effectively handled through the ZIP (constant impedance-constant current-constant power) load model. That voltage-dependent load behaviour greatly influences the power flow results, voltage profile and optimal placement and sizing of PVDG, especially when high penetration scenario is considered. This work presents the performance enhancement of IEEE 33 bus system with integration of multiple PVDG when real and experimental ZIP load modelling is incorporated in the distribution network. For optimal size and place selection, two optimization techniques, namely GA and PSO, are implemented, and results are compared to check complexity handling strength of those techniques under the presence of realistic load. Furthermore, the optimization framework included a reverse power flow penalty to restrict power flow in negative direction from load to substation to ensure reliable and safe operation of distribution system with high penetration of PVDGs.