The penetration level of distributed photovoltaic(PV)generation in the power distribution network has been increasing quickly

and sometimes the penetration level can exceed 100%. The power distribution network even feeds power into the transmission network when sunshine is strong. In this case

the dynamic characteristics of power distribution networks are determined by both the electrical loads and PVs. A dynamic equivalent model for power distribution networks with high penetration of PV is proposed. The proposed equivalent model contains a complex load model and a photovoltaic power station. Moreover

the dynamic trajectory sensitivity method is employed to select key equivalent parameters. Then

on the combined simulation platform of DIgSILENT and MATLAB

genetic algorithm is employed to identify the key parameters of the dynamic equivalent model. Finally

an integrated transmission and distribution network is simulated on DIgSILENT platform

and the simulation results demonstrate that the proposed dynamic equivalent model for distribution networks can ensure the accuracy of the transmission network transient simulation.