UPFC‐based line overload control for power system security enhancement

Abstract

A novel unified power flow controller (UPFC)‐based line overload control is presented in this study for power system security enhancement. The line loads of the transmission lines are monitored in real‐time operation and are controlled within their thermal limits through a feedback dynamic control of the UPFC. Firstly, the relationship between the line load of a transmission line and the active power setting of the UPFC is deduced. Secondly, the control law of the line overload control is developed, which adjusts the active power setting of the UPFC intelligently in case of line overloads. Thirdly, the implementations of the above control law are also provided. Using PSS/E, the case study is run in the Nanjing Western Power Grid, where the world's first modular multilevel converter‐based UPFC project, the Nanjing UPFC project, is located. The validity of the proposed line overload control is proved by the case study. The case study also indicates that the proposed line overload control is still valid with a 0.2 s delay, which further confirms the feasibility of the line overload control in practical engineering.