In the large-scale optimal power flow (OPF) online calculation

despite the highly efficient computation of the traditional direct current optimal power flow (DCOPF) method

it has poor computational accuracy owing to its total neglect of the impact of voltage and reactive power. A novel OPF method based on the pseudo direct current model is proposed

in which reactive power is introduced to correct active power balance equations. To further increase the computational efficiency

a simplified predictor-corrector interior point method

which predigests the program by modifying the inequality constraints of the OPF model

is used to solve the OPF problem. Finally

it follows from the simulation results of IEEE 30-bus

118-bus

300-bus

Polish 2 736-bus

and 3 120-bus test systems that the proposed method is successful and possesses good performance. This work is supported by National Natural Science Foundation of China (No. 51107032

No. 51277052

No. 61104045).