Modern power systems become more vulnerable to cyber threats due to their growing interconnectivity

interdependence

and complexity. Widespread deployment of distributed energy resources (DERs) further expands the threat landscape to the grid edge

where fewer cybersecurity protections exist. In this article

a systematic cyber-physical events demonstration

enabled by an integrated transmission

distribution

and communication co-simulation framework

is performed. It analyzes cyber risks to power grid under DER-enabled automatic generation control from different angles. Unlike existing works

the simulation captures millisecond-to-minutes frequency and voltage transient dynamics at a cross-region system scale.