Decentralized Approach to Detect and Eliminate Flapping Phenomena due to Flexible Resources

TL;DR

Flapping caused by uncoordinated switching of numerous discrete flexible resources and continuous controllers poses stability risks in low-inertia grids. We propose a decentralized approach that performs moving-window autocorrelation on local measurements to identify persistent oscillations and trigger device-specific probabilistic mitigations. The main contributions are a fully on-device detection algorithm based on normalized lag-band autocorrelation $\\rho[k]$ and mitigation strategies for DFRs, ULTCs, and AVRs, validated in WSCC 9-bus and IEEE 14-bus case studies. Results show robust discrimination between damped transients and true flapping, enabling rapid stabilization with minimal communication.

Abstract

This paper presents a decentralized methodology for detecting and mitigating flapping phenomena in power systems, primarily caused by the operation of discrete devices. The proposed approach applies moving-window autocorrelation to local measurements, enabling each device to autonomously identify sustained oscillations. Upon detection, a probabilistic, device-specific mitigation strategy is executed. Flexible demand resources (DFRs), under-load tap changers (ULTCs), and automatic voltage regulators (AVRs) are utilised to illustrate the performance of the proposed approach to both discrete and continuous-operation devices. Results show that the proposed method is robust and properly distinguishes damped oscillations from persistent flapping, allowing devices to independently recognize problematic operating scenarios and implement corrective actions accordingly.

Figures (12)

• Figure 1: DFR flapping detection and flag $\phi_i$.
• Figure 2: Aggregate DFR power injection.
• Figure 3: Flapping detection under reduced inertia.
• Figure 4: Frequency response: decentralized vs. centralized tuning.
• Figure 5: Two ULTC distribution system.