“Based on the theory of security domain, experts have proposed a complete process for regional comprehensive energy system security warning, established a security domain model, provided a method for calculating security boundaries, introduced fuzzy reasoning and fuzzy comprehensive evaluation methods, and proposed a warning method, including the selection and evaluation of warning indicators, security warning grading, analysis of warning reasons, and prediction of security trends. The effectiveness of this method has been verified through numerical examples, providing strong support for improving the security control capability of regional comprehensive energy systems.”