The Research On Electromagnetic Transient And Electromechanical Transient Calculation Based On Parareal Method

At present,most of the numerical calculation methods for electromechanical transients and electromagnetic transients are basically based on the traditional serial calculation mode,which inevitably leads to low efficiency.Parallel algorithms provide a good technical approach to solving this problem.Parallel algorithms can generally be divided into three methods: space parallel algorithm,time parallel algorithm and spatiotemporal parallel algorithm.When performing large-scale power system simulation numerical calculations,the space parallel algorithm will inevitably increase the number of network blocks,which will increase the communication between sub-networks and increase the communication delay.In addition,the uneven network segmentation can also result in uneven system load and wasted computing resources.Parallel time calculation provides an effective way to avoid the above situation.In order to further improve the efficiency of numerical simulation in power systems,a Parareal parallel computing method is applied to the numerical simulation of electromechanical transients and electromagnetic transients.Parareal is an algorithm that proposes solutions to problems in a time-parallel manner and is characterized by the parallelism of time.In addition,Parareal has a fast convergence rate and has been proved to be superlinearly convergent.To use the Parareal method for calculation,first the entire simulation time needs to be divided into several sub-intervals,and the initial values in each sub-interval are represented by a set of approximate solutions that satisfy the initial conditions of the network.Then use this set of initial values to solve the parallel calculations in each sub-range,and finally obtain a refined solution through the predictor-correction method.The dissertation divides the transient simulation of power system into two parts: electromagnetic transient simulation and electromechanical transient simulation.The Parareal method is used to obtain the electromagnetic transient response of the high voltage transmission line fault and the electromagnetic transient when the VSC-HVDC is disturbed.Response and Electromechanical Transient Stability of IEEE 145 Nodes The example tests show that the algorithm has fast convergence speed and high parallel efficiency,which can significantly improve the numerical simulation speed of electromechanical transient and electromagnetic transient in power system.