In recent years, load frequency control (LFC) systems employ open communication networks to meet the requirement of modern power system communication. However, some new risks were introduced into the LFC system, such as information staleness. The communication delay, which is a packet-centric metric, is used to portray the degree of information staleness in the existing works, whereas it cannot fully capture the freshness degree of information updates. In this paper, age-of-information (AoI) is introduced to describe the freshness of the whole information update process. An AoI-based stability criterion for sampled-data LFC systems is formulated. Results show that the LFC stability is dependent on AoI and the delay-dependent criteria is a special case of the AoI-dependent one

Age-of-information (AoI);load frequency control (LFC);stability