A Temperature Dependent Power Flow Model Considering Overhead Transmission Line Conductor Thermal Inertia Characteristics

The dependence of transmission line conductor resistance on temperature can be incorporated into power flow calculations via a temperature-dependent power flow (TDPF) formulation. Hence, a solution of the TDPF yields not only the traditional state variables of bus voltages and angles, but also the transmission line conductor temperature that can be then directly used to assess the thermal statuses of the lines. This paper proposes a TDPF model that uses a transient-state conductor electro-thermal model and thus captures the conductor thermal inertia characteristic. The formulation is especially useful while assessing the thermal status of overhead transmission lines in a given time period after a sudden change in the system state, such as the occurrence of a contingency or fast variation in the output of intermittent renewable generation. A simplified form of the overhead transmission line conductor electro-thermal model is used to reduce the computational burden while solving the TDPF equations.