Strength Evaluation by Inertia Constant for AC-DC Interconnected System

The traditional strength evaluation of AC-DC system only takes short circuit ratio into account,but the receiving-end AC system strength is also related with the system rotary inertia,namely,the inertia constant.In pscad/emtdc the stand-alone and multi-machine system model is set up.Thereby for the receiving-end stand-alone system,the electromagnetic transient is simulated considering the minimum inertia constant required to maintain the AC-DC system transient stability at different circuit ratio,and the inertia constant is obtained as an evaluation indicator of the AC-DC system strength.For the receiving-end multi-machine system,inertia constant is obtained by dynamic equivalent method.Simulation results verify the validity of these conclusions.