中文摘要：

在动态热定值实施背景及电热协调的概念基础上，探讨了输电线路发热及相关热载流极限在各种技术条件下的确定问题。针对存在输电能力受热限制的电网，深入研究了电热协调潮流及输电线路温度变化过程模型和算法的基础问题。通过电热协调潮流，即代数方程和微分方程的交替解算，给出适应电力系统运行模式各类扰动下的输电线路（尤其是关键输电线路）的温升变化过程的轨迹，从而期望达到实时通过输电线路的温度变化来判别输电线路载送能力是否受制约，充分挖掘现有电网潜在的输电能力，以提高系统运行的安全性和经济性，为进一步开展计及电热协调的电力系统运行调度理论研究铺设基础。

英文摘要：

Based on the implementation of dynamic thermal rating and the concept of electrothermal coordination, the determination of transmission lines heating and related thermal ratings in different technique conditions are discussed, and the models and modeling algorithms of transmission line temperature variation process are studied deeply aiming at the grid limited by line temperature. Through electrothermal coordination power flow, namely solve the algebraic equation and differential equation alternately, the temperature dynamics of transmission lines （critical transmission lines especially） adapting each fluctuation of power system operation scheme is analyzed, consequently whether the transmitting capacity is restricted can be differentiated directly by the real-time temperature of the lines, the potential transmitting capacity will be excavated, thus the security and economy of system operation are improved. The results lay the foundation for theoretical research of electric power system operation dispatching with electrothermal coordination.