Abstract: A digital simulation technique for wide area measurement system（WAMS）time delay is designed and implemented based on an analysis of the cause of WAMS time delay and the measured statistics results.Power system tasks based on WAMS are divided into soft real-time tasks and hard real-time tasks in the simulation process.The large step sub-process and the small step sub-process are adopted to simulate soft real-time tasks and hard real-time tasks at the same time,respectively.The small step sub-process produces the real-time measured values affected by the time delay at each simulation step.The large step subprocess produces measured values affected by the time delay and its time scale at each WAMS measuring step.The simulation technique presented for WAMS time delay has the following advantages:firstly,the time delay randomly generated according to a particular distribution or a sequence of measured time delay data can be simulated;secondly,on this basis,abnormal network status data,such as package loss,stick package,communication failure,can be simulated.Finally,the simulation technique for WAMS time delay is programmed in a real-time digital simulator（RTDS）.The random time delay and the measured time delay are tested in an RTDS to verify the effectiveness of the simulation technique,which is suitable for verifying the effects of time delay on the wide area controller in theory.