Advanced thermal rating and its application
Static thermal rating method converts the thermal constraint which represents the heat capacity of conductor into electric constraints, using static heat balance equation (HBE). It ignores the phenomenon of thermal inertia, and as a result, it limits the full exertion of line heat capacity, to some extent. Considering the asynchronous characteristic between electricity and heat, the definition of dynamic thermal rating is presented on the basis of dynamic heat balance equation which reflects the electrothermal coupling relationship. Dynamic thermal rating takes the operating temperature of conductor as the determinant limitation of heat capacity. Then a new concept of advanced thermal rating is proposed, considering that the temperature and power system operation dispatch are interlinked. Its application foreground is expatiated by the examples of advanced dispatch and security dispatch. All the above provide a foundation for an in-depth research of electrothermal coordination in dispatch operation of power system.