Multi-stage Security Constrained OPF Using Dynamic Thermal Rating

In order to enhance the security of power system after the contingency occurrence, a multi-stage security constrained OPF (MSCOPF) model including preventive, post-contingency and corrective stages is established in this paper. Dynamic thermal rating (DTR) is implemented in the second stage for taking full advantage of the line short-term overload capacity. An approximate calculation based on linear differential equation and piecewise linearization is presented to describe the dynamic change of conductor temperature. Then temperature constraints are designed in the post-contingency stage. The case studies illustrate that MSCOPF has the equivalent security compared with preventive security constrained OPF (PSCOPF), but its operating cost is slightly higher than the result of corrective security constrained OPF (CSCOPF). Furtherly, error analysis shows that the maximum error for the simulation of DTR is less than 1 % and preferable segments of piecewise linearization for steady-state temperature function are around 40.