Distributed Stability Indices of a Cluster of Nonlinear Heterogeneous Dynamical Devices: Aggregation and Correction

The access of massive heterogeneous devices to the power grid has been dramatically increasing the complexity of power system dynamics. In this situation, traditional power system stability analytics in a centralized manner may fail due to the curse of dimensionality. The model-based aggregation methods can reduce the scale of the system model, but may encounter obstacles when dealing with heterogeneous dynamical devices. This paper proposes an aggregation method for reducing the complexity of stability analysis. In contrast to conventional model-based aggregation methods, our method is based on the newly-proposed distributed stability index (DSI). To this end, we first explain how to decide the aggregation areas in terms of DSI. Then, the aggregated DSI of a cluster of devices is derived. Afterward, a correction method is established to compensate for the loss effect caused by transmission impedance. Combining the proposed aggregation and correction methods, the practical procedure for stability assessment is presented. Finally, the results are verified by simulations on the IEEE-33 distribution system.