Impact of Communication Delay and Sampling on Small-Signal Stability of IBR-rich Power Systems

TL;DR

This paper investigates how communication delays and sampling in inverter-based resources affect the small-signal stability of power systems, highlighting their unique impacts and proposing mitigation strategies.

Contribution

It provides a detailed analysis of communication delay and sampling effects on IBR stability, emphasizing the need for improved stability assessment methods.

Findings

Communication delay significantly impacts system stability.

Sampling period influences oscillation characteristics.

Strategies to mitigate delay and sampling effects are proposed.

Abstract

The growing adoption of inverter-based resources (IBRs) has introduced unprecedented dynamics in power systems, resulting in oscillations across a broad spectrum of frequencies. Communication delay between the plant-level control and the inverter-level control in IBR plants has been recognized as one of the causes of such oscillations and a factor that impacts the system's stability. The control signals from the plant-level controller also experience sampling, with the sampled values held constant by the hold elements for the duration of the sampling period. This also has a bearing on the response of IBR plants. In this paper, we analyze the impacts of communication delay and sampling of control signals between plant-level control and inverter-level control of grid-following IBR plants on the small-signal stability of power systems. The underlying fundamentals of communication delay and sampling are revisited to explain the observed responses. Our findings emphasize the unique effects of communication delay and sampling period on the stability of IBR-rich power systems and suggest strategies to mitigate their detrimental impacts. The work also highlights the need for more accurate approaches for small-signal stability analysis of such systems.