Full system constraint formulations (power, gas, and heat)

This file provides the complete mathematical formulations of system constraints used in the bi-level optimization model for integrated energy systems, including electricity, gas, and heat networks. The constraints cover power balance equations, device operation limits, coupling models, and thermal energy flow relations. These formulations are referenced in the main paper but are presented here in full due to space limitations.

本文件完整给出了面向包含电、气、热网络的综合能源系统（integrated energy systems）的双层优化模型（bi-level optimization model）所采用的系统约束的完整数学表述，涵盖功率平衡方程（power balance equations）、设备运行限值（device operation limits）、耦合模型（coupling models）与热能流动关系（thermal energy flow relations）。上述数学表述已在正文中被引用，但因版面限制，本文将其完整呈现于此。