Efficient Simulation of Temperature Evolution of Overhead Transmission Lines Based on Analytical Solution and NWP

1 Abstract --Transmission lines are vital components in power systems. Outages of transmission lines caused by over-temperature is a major threat to system reliability, so it is necessary to efficiently simulate line temperature under both normal operation conditions and foreseen fault conditions. Existing methods based on thermalsteady-state analyses cannot support the simulation of transient temperature evolution, and thus cannot provide timing information needed for taking remedial actions. Moreover, conventional numerical method requires huge computational efforts and barricades system-wide analysis. In this regard, this paper derives an approximate analytical solution of transmission-line temperature evolution enabling efficient analysis on multiple operation states. Considering the uncertainties in environmental parameters, the region of over-temperature is constructed in the environmental parameter space to realize the over-temperature risk assessment in both the planning stage and real-time operations. A test on a typical conductor model verifies the accuracy of the approximate analytical solution. Based on the analytical solution and numerical weather prediction (NWP) data, an efficient simulation method for temperature evolution of transmission systems under multiple operation states is proposed. As demonstrated on a Northeast Power Coordinating Council (NPCC) 140-bus system, it achieves over 1000 times of efficiency enhancement, verifying its potential in online risk assessment and decision support. Index terms --Transmission line temperature, dynamic line rating, situational awareness, numerical weather prediction (NWP), kmeans clustering, analytical solution, N-k contingency analysis.