An Online Event-Based Grid Impedance Estimation Technique Using Grid-Connected Inverters

An increasing intake of grid-connected inverters could change the characteristics low voltage networks including equivalent grid impedance seen by each inverter at its point common coupling. This can impact overall performance inverters, and thus it becomes necessary for to estimate online. However, there are some challenges when comes estimation using inverters. These include accuracy associated power quality issues that mainly related amplitude, frequency, time period injected disturbance into grid. To address these challenges, a novel online event-based technique is proposed in this article. combines an active technique, based on variations inverter's output [active (P) reactive (Q) variations], continuous monitoring positive-sequence amplitude PCC voltage. The main advantage only performs deliberate perturbation P Q if certain magnitude change. will significantly reduce occurrence required PQ variations, minimizing losses quality. Simulation experimental results system validate technique.