Analysis On UHV AC/DC Tie-line Interaction

A simplified model is developed based on the network. The variation curves of power flow on the UHVAC tie-line,is analyzed when the DC line is double-pole blocked. Rotor angle stability margin between the two power grids is calculated. The sensitivity factors of stability margin are analyzed. Equivalent data could be calculated by aggregating Sanhua power grid with the weighting-mean aggregation method. After Substituting the aforementioned equivalent data into equation, it could be concluded that the total power injecting into the receiving end will increase when power flow on the AC tie-line is decreased. Based on Sanhua power grid, the accuracy and effectiveness of the proposed method has been proved in the case study.The security of North China-Center China-East China synchronous power grid was studied. Emergency load shedding, Under Frequency Load Shedding (UFLS) was put in use to enhance the stability of the grid.