Integrating three-phase load flow and short-circuit current calculation for a low voltage system

This paper summaries a dedicated approach to solve three-phase load flow an d calculate unbalanced short-circuit current simultaneously for low voltage systems without using the conventional symmetrical components. As the unba lanced load and the neutral and shock voltages have to be modeled, the netw ork equations including the representation of the neutral and grounding con ductors are formulated entirely in phase coordinates. Test results demonstr ate the ability in modeling the untransposed cable parameters and the influ ence of the unbalanced load currents. More accurate results can thus be obt ained as compared with other methods of calculation. Many interesting pheno mena such as unbalanced load flow, different voltages appearing at various sections of the neutral and grounding conductors, effects of the disconnect ion of the source earthing, and any open-circuit fault can all be simulated . (C) 2000 Elsevier Science S.A. All rights reserved.