Speedup and synchronisation overhead analysis of Gauss-Seidel type algorithms on a Sequent balance machine

The parallelisation and implementation of Gauss-Seidel (G-S) algorithms for power flow analysis have been investigated previously. Numerous runs to demonstrate the speedup have been illustrated on a Sequent Balance shared-memory multi-instruction, multidata access (SM MIMD) machine. The authors extend the idea and investigate-the effects of acceleration factors. It is shown on systems ranging from teens to thousands that when the acceleration factors are used, the implementation using colour-by-colour synchronisation is more reliable and has better convergence rate, even though it takes a longer time to synchronise. The authors also analyse the dependence of synchronisation overhead in terms of system sizes, network connection and number of processors. Comparisons between G-S and fast decoupled load-flow algorithms are also made. The implications on nCUBE implementations are also discussed. It is also shown that the idea of parallel G-S algorithm can be easily extended to solve the transient stability problem which involves a set of algebraic differential equations.