Next-Generation Grid Codes: Towards a New Paradigm for Dynamic Ancillary Services

TL;DR

This paper proposes a new framework for power grid codes that guarantees stability and performance of dynamic ancillary services using decentralized, frequency-domain criteria, enabling more reliable and flexible power system operation.

Contribution

It introduces a non-parametric, decentralized approach for certifying stability and performance in power systems, facilitating the development of future grid codes.

Findings

Provides local frequency-domain stability certificates for devices.

Establishes bounds on frequency and voltage performance metrics.

Ensures closed-loop stability through decentralized verification.

Abstract

This paper introduces a conceptual foundation for Next Generation Grid Codes (NGGCs) based on stability and performance certificates, enabling the provision of dynamic ancillary services such as fast frequency and voltage regulation through decentralized frequency-domain criteria. The NGGC framework offers two key benefits: (i) rigorous closed-loop stability guarantees, and (ii) explicit performance guarantees for frequency and voltage dynamics in power systems. Regarding (i) stability, we employ loop-shifting and passivity-based techniques to derive local frequency-domain stability certificates for individual device dynamics. These certificates ensure the closed-loop stability of the entire interconnected power system through fully decentralized verification. Concerning (ii) performance, we establish quantitative bounds on critical time-domain indicators of system dynamics, including the average-mode frequency and voltage nadirs, the rate-of-change-of-frequency (RoCoF), steady-state deviations, and oscillation damping capabilities. The bounds are obtained by expressing the performance metrics as frequency-domain conditions on local device behavior. The NGGC framework is non-parametric, model-agnostic, and accommodates arbitrary device dynamics under mild assumptions. It thus provides a unified, decentralized approach to certifying both stability and performance without requiring explicit device-model parameterizations. Moreover, the NGGC framework can be directly used as a set of specifications for control design, offering a principled foundation for future stability- and performance-oriented grid codes in power systems.