A New Fully Parallel BBDF Method in Transient Stability Simulations

Parallel computing is an effective tool to improve the efficiency of transient stability simulations. The method of forming the bordered block diagonal form matrix (BBDF method) is widely used. However, as the number of subnets increases, the computational complexity of the cut-node network and the communication overhead become large quickly, which limits the efficiency of the method. A new fully parallel BBDF (FBBDF) method is proposed to solve this problem. During the iterative solutions of network equations, the FBBDF method parallelizes the solutions of subnets and the solution of the cut-node network by utilizing the result of the cut-node network at previous iteration step for the solutions of subnets at current iteration step. The calculation time can be reduced from the total solution time of the largest subnet and the cut-node network to the largest solution time of subnets and the cut-node network. The whole network is divided via the factorization path graph. The test results show that the FBBDF method requires less computing time than the classic BBDF method and can increase the speedup of parallel computing to more than 16x with 40 threads in a 24886-node actual power system.