Network-Secure Envelopes Enabling Reliable DER Bidding in Energy and Reserve Markets

As our power system modernises to embrace consumer-owned distributed energy resources (DER), network operators must ensure a safe and reliable operation while enabling consumers to trade their flexibility in the wholesale market. To enable this, we obtain network-secure operating envelopes that facilitate participation of consumers in energy and reserve markets. Given the distributed nature of the real-world problem, we use the alternating direction method of multipliers (ADMM) to optimise for operating envelopes such that any market action of consumers within these envelopes satisfies the distribution network constraints. To guarantee that the uncertainty realisation in live operation neither leads to network infeasibilities (due to exceeding the operating envelope) nor penalises DER-owners (due to market bid violation), we introduce a piecewise affinely adjustable robust bidding approach that can compensate for uncertainty variations in real-time. We also open up network capacity and minimise its losses, by proposing an additional piecewise affine Q-P controller that exchanges inverter reactive power with the grid. Our results on a 69-bus distribution network highlight the effectiveness of our proposal compared to alternative approaches.