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Contingency-constrained economic dispatch with safe reinforcement learning

Michael Eichelbeck, Hannah Markgraf, Matthias Althoff

TL;DR

The paper tackles contingency-aware economic dispatch in renewable-rich microgrids by integrating a provably safe reinforcement learning controller with a formal safety layer. It encodes a time-dependent islanding contingency through set-based backwards reachability and enforces safety via action projection into a safe set represented by constrained zonotopes, enabling real-time operation. The approach is demonstrated on a residential microgrid using real-world measurements, showing that the safe agent satisfies islanding constraints and yields higher performance than a baseline without full safety guarantees. This work provides certifiable safety for RL-based economic dispatch in zero-carbon power systems and offers a tractable framework for future extensions to more complex network models.

Abstract

Future power systems will rely heavily on micro grids with a high share of decentralised renewable energy sources and energy storage systems. The high complexity and uncertainty in this context might make conventional power dispatch strategies infeasible. Reinforcement-learning based (RL) controllers can address this challenge, however, cannot themselves provide safety guarantees, preventing their deployment in practice. To overcome this limitation, we propose a formally validated RL controller for economic dispatch. We extend conventional constraints by a time-dependent constraint encoding the islanding contingency. The contingency constraint is computed using set-based backwards reachability analysis and actions of the RL agent are verified through a safety layer. Unsafe actions are projected into the safe action space while leveraging constrained zonotope set representations for computational efficiency. The developed approach is demonstrated on a residential use case using real-world measurements.

Contingency-constrained economic dispatch with safe reinforcement learning

TL;DR

The paper tackles contingency-aware economic dispatch in renewable-rich microgrids by integrating a provably safe reinforcement learning controller with a formal safety layer. It encodes a time-dependent islanding contingency through set-based backwards reachability and enforces safety via action projection into a safe set represented by constrained zonotopes, enabling real-time operation. The approach is demonstrated on a residential microgrid using real-world measurements, showing that the safe agent satisfies islanding constraints and yields higher performance than a baseline without full safety guarantees. This work provides certifiable safety for RL-based economic dispatch in zero-carbon power systems and offers a tractable framework for future extensions to more complex network models.

Abstract

Future power systems will rely heavily on micro grids with a high share of decentralised renewable energy sources and energy storage systems. The high complexity and uncertainty in this context might make conventional power dispatch strategies infeasible. Reinforcement-learning based (RL) controllers can address this challenge, however, cannot themselves provide safety guarantees, preventing their deployment in practice. To overcome this limitation, we propose a formally validated RL controller for economic dispatch. We extend conventional constraints by a time-dependent constraint encoding the islanding contingency. The contingency constraint is computed using set-based backwards reachability analysis and actions of the RL agent are verified through a safety layer. Unsafe actions are projected into the safe action space while leveraging constrained zonotope set representations for computational efficiency. The developed approach is demonstrated on a residential use case using real-world measurements.
Paper Structure (17 sections, 25 equations, 3 figures, 2 tables, 1 algorithm)

This paper contains 17 sections, 25 equations, 3 figures, 2 tables, 1 algorithm.

Figures (3)

  • Figure 1: Schematic representation of the first two steps of Algorithm \ref{['alg:backwards_reachability']} for a system with two energy storage systems (computed sets in grey).
  • Figure 2: Islanding constraint satisfaction during an exemplary day for baseline agent, safe agent, and safe agent without islanding safeguard.
  • Figure 3: Reward, safety violation, cost and penalty curves for training. Logarithmic scaling is used in all plots with horizontal lines.