| The implicit trapezoidal method is widely used in electromagnetic transient simulation as the core algorithm of power system electromagnetic transient numerical calculation.However,the implicit trapezoidal method can not meet the requirements of efficient electromagnetic transient simulation of power system due to its small step size and lack of L-stability,In other words,the oscillation characteristics in the case of mutation cannot be effectively suppressed.In order to improve the efficiency of electromagnetic transient calculation,more numerical calculation methods and more parallel methods are applied to the simulation of power system.Therefore,this paper focuses on how to effectively improve the efficiency of electromagnetic transient calculation.In recent years,more and more multilevel implicit numerical methods have become active in electromagnetic transient computation with the advantage of large length simulation.However,multi-stage means the introduction of interior points,increasing the amount of calculation,and is not suitable for direct application in electromagnetic transient calculation.Among many multilevel implicit methods,the integral scheme of DQM and 2 and3 order Radau ⅡA is simple.In this paper,the two algorithms are combined with the parallel method,and A preliminary study is carried out on the electromagnetic transient parallel calculation method based on DQM and 2 and 3 order Radau ⅡA method.Firstly,a fast calculation method of electromagnetic transient state based on differential quadrature method is proposed.By using the characteristics of V transformation of the differential quadrature method,the coefficient matrix whose dimension is increased due to the introduction of interior points is partitioning,and the simulation of large length is realized while the calculation amount of inverse matrix is maintained.Numerical examples show that the algorithm achieves effective acceleration ratio.Based on the differential quadrature method(DQM),a parallel electromagnetic transient algorithm based on the three-order differential quadrature method is proposed.The coefficient matrix whose dimension is increased due to the introduction of interior point is transformed into the inverse of the matrix with low maintenance number by equal transformation.Two examples are used to prove the effectiveness of the algorithm.In order to further improve the efficiency of electromagnetic transient computation,A parallel electromagnetic transient computation algorithm based on the 2-order and 3-order Radau ⅡA method is also proposed.According to the characteristics of the selected algorithm,the coefficient matrix can be decomposed into a diagonal block matrix and a highly sparse constant coefficient matrix.Based on this characteristic,it is firstly divided into blocks,and finally,it is combined with Sherman-Morrison inverse formula to realize parallel inverse.Block processing also reduces the amount of serial calculation,so it further improves the calculation speed of electromagnetic transient based on Radau ⅡA method,and the effective acceleration ratio is obtained. |
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