Age-of-Information-Aware Load Frequency Control and Stability Analysis

Abstract

Nowadays, modern load frequency control (LFC) systems employ an open communication system, which causes information staleness inevitably to arise. This issue can degrade the regulation performance of LFC and even threaten stability. This thesis introduces age-of-information (AoI) into LFC to describe the information freshness at the control center. Unlike communication delay, AoI can provide real-time information state based on information update rate. In this thesis, a muti-area LFC-AoI model is built to evaluate the update rate effect on LFC performance. Then, an AoI-based stability criterion for discrete LFC systems is built. After that, the AoI margin is proposed and compared with the communication delay margin. Next, an algorithm is introduced to design a PI-type controller based on a specific update rate for a one-area power system. Then, fluctuation of LFC frequency as a performance metric guides the power system to choose the right update rate. Case studies are carried out based on the one-area power system. Simulation results show the necessity of considering the update rate effect on LFC performance, the AoI margin is larger than the delay margin and the large extent depends on the update rate. And the performance of LFC can be optimized under the right update rate and designed PI-type controller.