电热协调(ETC)理论的提出对实时环境下输电元件载荷能力的有效利用具有重要意义,但由于电与热之间的紧密耦合,使电力系统的潮流计算变得复杂,文中针对该问题进行了深入研究。将输电线路热动态微分方程引入到现有的电力系统潮流模型之中,利用隐式梯形的差分方法将该微分方程代数化,使输电线路温度成为电力系统运行的一个新的状态量,从而提出了计及电热耦合的潮流计算数学模型,并在推导得到牛顿法求解该模型的修正方程基础上,进一步提出了适应电热耦合处理的简化计算方法,该模型和算法实现了电气量和其温度的统一处理,不仅反映潮流的电的信息,而且能够提供输电线路热惯性的动态过程,即温度变化信息,从而实现输电线路载荷能力由温度评判的目的。最后通过算例分析验证了该模型和算法的有效性,为进一步开展电力系统运行调度中的电热协调理论研究奠定了基础。
Electro-thermal coordination theory is important for the effective on-line utilization of the load carrying capacity of transmission components. However, the close coupling between electricity and heat complicates the power flow calculation. Aimed to solve this problem, the dynamic heat balance equation is introduced into power flow calculation model. Then a new power flow calculation model in which temperature is considered as a state variable by using implicit trapezoid discretization method is proposed, and the power flow calculation model considering the coupling of electricity and heat is formed. In addition, based on the deduced correction equation of Newton method a simplified algorithm which adapts to the electricity-heat coupling problem is proposed. The uniform transaction of electrical variables and temperature is realized by this algorithm. It provides not only the electrical information of power flow calculation, but also the thermal inertia process. Consequently, the carrying capacity of a conductor can be determined by its temperature. Finally, a simulation is carried to demonstrate the validity of the model and algorithm proposed in this paper.