Toward Distributed Stability Analytics for Power Systems with Heterogeneous Bus Dynamics

TL;DR

This paper introduces a local passivity index condition that ensures system-wide stability in heterogeneous power systems, accommodating diverse bus dynamics and enhancing transient stability through proper control design.

Contribution

It derives a passivity-based stability condition applicable to various bus models, facilitating scalable and adaptable stability analysis for complex power systems.

Findings

The passivity index condition guarantees stability in lossless systems.

Proper control can achieve the passivity condition for different bus dynamics.

Simulations confirm the effectiveness and tightness of the proposed condition.

Abstract

The stability issue emerges as a growing number of diverse power apparatus connecting to the power system. The stability analysis for such power systems is required to adapt to heterogeneity and scalability. This paper derives a local passivity index condition that guarantees the system-wide stability for lossless power systems with interconnected, nonlinear, heterogeneous bus dynamics. Our condition requires each bus dynamics to be output feedback passive with a large enough index w.r.t. a special supply rate. This condition fits for numerous existing models since it only constrains the input-output property rather than the detailed dynamics. Furthermore, for three typical examples of bus dynamics in power systems, we show that this condition can be reached via proper control designs. Simulations on a 3-bus heterogeneous power system verify our results in both lossless and lossy cases. The conservativeness of our condition is also demonstrated, as well as the impact on transient stability. It shows that our condition is quite tight and a larger index benefits transient stability.