A Hybrid Γ-Model for Distribution Feeders: Linear Parameter Estimation Using Unsynchronized Terminal Measurements

Accurate estimation of parameters for Distribution Network Feeders (DNFs) is crucial yet quite challenging, especially with limited synchronized measurements. This letter introduces a novel Hybrid Γ-Model (HGM) that leverages the circuit properties of DNFs to establish a linear relationship between unknown feeder parameters and unsynchronized terminal measurements. By combining two symmetrical Γ-models, the HGM effectively mitigates the inaccuracies and biases of simplified models. This model balances the accuracy of the equivalent П-model with the linearity of the short-line and Γ-models. An effective parameter estimation method is developed based on HGM, operating without requiring synchronized data. This method is applicable to both overhead lines and underground cables and is particularly useful in the latter case, where shunt susceptance is more significant. By avoiding iterative solutions, the proposed method ensures convergence and eliminates the risk of multiple outcomes.