A Non-Invasive Estimation Technique for Wide Band Grid Side Thevenin's Impedance

In this paper, the authors have discussed a novel technique for estimation of the wide band Thevenin's grid impedance. A non-invasive technique has been proposed to estimate the missing impedance data recursively from the sampled voltage and current from the point of common coupling. The algorithm works on an initial learning and realtime tracking approach. The proposed technique benefits an impedance monitoring algorithm and can also be used for realtime stability analysis based on the impedance stability theory. The efficacy of the technique has been tested by computer simulations of a power system contingency when a grid tied inverter is connected to the IEEE 9 bus benchmark system.