Delay-Aware Semantic Sampling in Power Electronic Systems

TL;DR

The paper tackles data availability attacks in power electronic systems that disrupt time-synchronized sampling and coordinated control. It introduces a delay-aware semantic sampling framework that leverages inner control loop dynamics and semantic attributes—Freshness, Relevance, and Priority—to reconstruct delayed information locally and compensate for delays without requiring training. The approach is distributed and model-agnostic, using process-aware sparse sampling and a Lyapunov-based convergence analysis to guarantee stability, with validation on a real-time OPAL-RT setup applied to a modified IEEE 37-bus system. Results show improved convergence and resilience under latency attacks, data dropouts, and TSAs, including robustness to dynamic cyber graph changes and compatibility with IEC 61850 communication protocols, indicating strong practical potential for PES resilience and scalability.

Abstract

In power electronic systems (PES), attacks on data availability such as latency attacks, data dropouts, and time-synchronization attacks (TSAs) continue to pose significant threats to both the communication network and the control system performance. As per the conventional norms of communication engineering, PES still rely on time synchronized sampling, which translates every received message with equal importance. In this paper, we go beyond event-triggered sampling/estimation to integrate semantic principles into the sampling process for each distributed energy resource (DER), which not only compensates for delayed communicated signals by reconstruction of a new signal from the inner control layer dynamics, but also evaluates the reconstruction stage using key semantic requirements, namely Freshness, Relevance and Priority for good dynamic performance. As a result, the sparsity provided by event-driven sampling of internal control loop dynamics translates as semantics in PES. The proposed scheme has been extensively tested and validated on a modified IEEE 37-bus AC distribution system, under many operating conditions and noisy environment in OPAL-RT environment to establish its robustness, model-free design ability and adaptive behavior to dynamic cyber graph topologies.

Figures (17)

• Figure 1: Semantic information exchange and estimation in PES -- sparse event-driven sampling from local error measurements steer the estimation and reconstruction process during latency attack/data dropout/TSAs.
• Figure 2: (a) The modified IEEE 37-bus islanded AC distribution system powered by seven DERs is shown. (b) The block diagram of cyber-physical DER with primary and DSC architecture is presented. The DSC receives local measurements ($\mathrm{\sigma}_j$) and neighbouring measurements ($\mathrm{\sigma}_m$) as input to generate frequency and voltage correction terms ($\Delta \omega$ and $\Delta \mathrm{V}$). Note that the merging units (MUs) receive the timing information from GPS satellite. These time-stamped measurements are then used by the controllers for generating control signals, which can directly affect the control operation of the system.
• Figure 3: (a) Latency attack and data dropout; and (b) TSA.
• Figure 4: Spoofing procedure for TSA. (a) Aligning TSA code phase with authentic one; (b) initiating attack by increasing TSA signal power; and (c) gradual alteration of the victim's code to introduce timing error.
• Figure 5: (a) Proposed delay-aware semantic sampling scheme. (b) Deployment of the proposed scheme in real-time simulation testbed. The testbed is interfaced with Ethernet to facilitate establishment of IEC 61850 sampled values protocol.