Fast Hosting Capacity Analysis for Thermal Loading Constraint Using Sensitivity-based Decomposition Method

High solar photovoltaic (PV) penetration can cause reverse power flows that exceed the thermal loading limits of distribution transformers, lines, and other equipment. PV hosting capacity refers to the amount of solar PV that a feeder location can accommodate without adverse power quality, reliability, or safety impacts. Previous work has established that the nodal voltage magnitude has a quasi-linear relationship with the feeder load and PV power injections. However, the analysis of circuit thermal limits in hosting capacity is more difficult due to the nonlinear nature of the line current magnitude. This paper uses a decomposition method that combines real and reactive power flow manifolds to accurately estimate the branch current magnitude and consequently, the thermal hosting capacity. The method requires solving only a small number of nonlinear AC power flows and has the potential to significantly speed up PV hosting capacity analysis. The accuracy of the proposed method is evaluated on the IEEE 123 bus test circuit.