At present

the highest voltage of AC transmission lines in service in China has reached 1 000 kV.To accurately calculate the power frequency electric field of EHV/UHV transmission line

the authors propose a calculation model with consideration of conductor corona discharge on the basis of the charge simulation method（CSM）.This model simulates the motion and recombination process of the space line charges in the ion flow field around the conductors in entire cycles until the power loss reaches a steady state.The ground level power frequency electric field is determined by the charges in conductors and surrounding space.The innovation of the model is that the quantity of electricity per unit length of each sub-conductor is simulated by one line charge.Simulation results are compared with the results in literatures to verify the correctness of the proposed model.The electric field on ground underneath 1 000 kV3-phase 8-bundle AC transmission lines is simulated using this model

and the results are compared with the measured values.Conclusion is drawn that corona discharge leads to about 5% enhancement in the power frequency electric field.