Fast frequency response with heterogeneous communication delay management under the SCION Internet architecture

TL;DR

This work proposes a SCION-enabled framework for real-time FFR that accommodates heterogeneous communication delays between a system operator and flexible devices (DERs and CLs). It develops a multi-pole frequency dynamics model and derives a closed-form nadir analysis, enabling a cyber-physical co-optimization that jointly selects latency-minimizing routing paths and FFR reserves. To overcome NP-hardness, it introduces a heuristic reserve-allocation algorithm built around lowest-latency routing via DMTP, an equivalent DER step-response model, ascending-latency sorting, and nadir-based computation acceleration. Case studies with wide device counts and real SCION latency data show SCION reduces latency tails, and the heuristic achieves near-optimal reserve costs with real-time computation feasibility. The approach offers a practical path to scalable, latency-guaranteed FFR using publicly accessible SCION networks.

Abstract

System operators can increasingly exploit distributed energy resources (DERs) and controllable loads (CLs) to provide frequency response services. In conventional practice, communication between the system operator and flexible devices relies on the Border Gateway Protocol (BGP)-based Internet. However, existing BGP-based architectures face challenges in providing latency-guaranteed control, while direct private and proprietary communication networks lead to additional deployment and maintenance costs. In contrast, the SCION-based Internet architecture supports latency-minimum path selection, which makes it suitable for latency-sensitive frequency contingency services such as fast frequency response (FFR). Hence, this paper proposes a real-time reserve dispatch framework to optimally select a portfolio of flexible devices to deliver FFR services using the SCION-based Internet. First, an analytical expression of the system frequency dynamics with respect to heterogeneous communication latencies is derived. Next, a cyber-physical co-optimization model is formulated to jointly schedule communication paths and physical flexibility resources for real-time FFR provision. To improve the computation efficiency, we propose a heuristic FFR allocation algorithm to approximate the optimal response portfolio, integrating contributions from both DERs and CLs. Numerical case studies demonstrate the benefits of the proposed algorithm and its capability to approximate the optimality of the reserves allocation while significantly reducing the computation time.

Figures (6)

• Figure 1: Structure of FFR dispatch architecture through the SCION Internet framework
• Figure 2: Fast frequency response with diverse communication latencies in a cyber-physical system architecture using SCION internet
• Figure 3: Equivalent step response model for frequency dynamics of DER $d$
• Figure 4: Comparison of the average communication latencies between the system operator and flexible loads with respect to the SCION-based Internet network and BGP-based Internet network measured by (a) empirical cumulative distribution function, and (b) histogram of latency measurements.
• Figure 5: Comparison between the global optimization solver and the proposed heuristic algorithm evaluated by (a) the cost of FFR reserves and (b) the frequency nadir.