An Equivalent Modeling Method for Multi-port Area Load Based on the Extended Generalized ZIP Load Model

To model the load area and simplify the electrical network, a multi-port area load equivalent modelling method (ALEEM) based on the extended generalized ZIP load model (EGZIP) is proposed. Different from the traditional ZIP load, the EGZIP load model incorporates the voltage magnitudes and voltage phase angles of all boundary buses, which can equivalently model the area load with multiple boundary buses more accurately. The load flow calculation considering the EGZIP is derived and analyzed. Also, based on the hierarchical and partitioning characteristics of the power grid, a multi-port equivalent strategy is proposed to reduce the number of parameters to be identified in the equivalent model. For parameter identification, the currents measured at varying operation conditions on the boundary bus are used to construct the least square estimation (LSE) problem. The interior point method is used to identify the model parameters. The simulation test conducted on the 87 bus system proves the equivalent model derived from the proposed ALEEM based on EGZIP has higher accuracy and the multi-port equivalence strategy can reduce both the number of parameters to be identified and the time consuming on equivalent process.