A Dynamic-Phasor Simulation Method with Sparse Tableau Formulation for Distribution System Analysis: A Preliminary Result

Abstract

To realize smarter distribution networks, simulations play an essential role for the design and coordination of various kinds of distribution equipment. The electromagnetic transient (EMT) simulation that can reproduce detailed three-phase waveforms is suitable for such simulations but requires a large amount of computational resource thus a long computation time. There are situations where very fast transients are not of interest but relatively slow transients superimposed on the fundamental frequency with unbalanced impedances are of interest, and the design and coordination simulations mentioned above fall into this category. In such situations, the simulations can be significantly accelerated by the theory of dynamic phasors. This paper proposes a dynamic-phasor simulation method with sparse tableau formulation for distribution system analysis, and its preliminary result is presented. The sparse tableau formulation which allows automatic generation of dynamic-phasor circuit equations is capable of handling dependent sources necessary to model ideal transformers and suitable for parallel computation. Using the proposed method, the dynamics of a solar farm connected to a distribution line is calculated with a large time step, and it is confirmed that the result is practically the same as that obtained by the corresponding EMT simulation that requires a fairly small time step.