Parallel processing in dynamic simulation of power systems

Abstract

The dynamic behaviour of a large interconnected electric power system is characterized by a simultaneous set of nonlinear algebraic and ordinary differential equations. The solution is obtained by numerical methods and the simulation of the transient behaviour for a few seconds after a fault is the standard analytical procedure used in planning and operational studies of the system. The need for on-line simulation in near real time for more efficient operation has encouraged the search for faster solution methods and the use of parallel computers for this purpose has attracted the attention of many researchers. The success of paraUelization depends on three factors: the problem structure, the computer architecture, and the algorithm that takes maximum advantage of both. In this problem, the generator equations are only coupled through the electrical network providing some parallelization in (variable) space, and a solution is needed at each time step leading to some parallelization in time (waveform relaxation). However, since the problem formulation is not completely decoupled, parallel algorithms can only be developed by trading off any relaxation with a degradation in convergence. The fastest sequential algorithm used today is the combination of implicit trapezoidal integration with a dishonest Newton solution. The Newton algorithm is not parallel at all but has the fastest convergence while a Gauss-Jacobi algorithm is completely parallel but converges very slowly. A relaxation of the Newton algorithm appears to be a good compromise. As for the parallel hardware, the coupling seems to require significant communication between processors thus favouring a data-sharing architecture over a messagepassing hypercube. Special architectures to match the problem structure have also been an area of investigation. This paper elaborates on the above issues and assesses the present state-of-the-art.

A Review of High-Performance Computing and Parallel Techniques Applied to Power Systems Optimization

“…A few parallel power system study reviews have been conducted throughout the development of computational hardware. Some had similar goals to this paper reviewing HPC applications for power systems [42] [43] and on distributed computing for online real-time applications [44]. Computational paradigms changed exponentially, reducing those reviews to pieces of history.…”

Localization and latency concepts applied to time simulation of large power systems

“…Clearly, the network, which couples all system components, does not allow a complete algorithm parallelization. To deal with this bottleneck, several approaches in the past resorted to relaxation, as outlined in the Introduction [4]. In this work, it was chosen not to do so, in order to preserve the convergence properties of a direct Newton method and avoid performing several solutions over the same time window.…”

“…To achieve faster simulations parallel processing attracted many researchers. Indeed, power system time-domain simulation presents some characteristics that may make it suitable for parallelization in space and in time [4]. Parallelization in space takes advantage of the power system structure in which components such as generators, loads, compensators, etc.…”