Fault energy implications of distributed converter interfaced generation : A case study of an underground mine grid

Abstract: Adding Power Electronic Interfaced Devices (PEID) generation to grids is an increasing trend because of the concurrent development of better power electronic converters and a greater interest in a better utilisation of energy resources. Small and dispersed energy sources that would previously not be worth introducing into the grid is becoming more and more viable and other potential benefits such as better control of voltage levels and smoothing out load changes also spur this development. But while there are great potential benefits of the controllability of these devices there are also risks when existing protection systems are made for the linear behaviour of traditional synchronous generators. This thesis describes the peculiarities of the short circuit behaviour of PEID generators and how this affects the short circuit energy levels in terms of short circuit current, I2t and incident arc energy. Using simulation, it is shown that in the case of the specific mine grid studied, the incident arc energy increases substantially and that this need to be considered when evaluating installation of PEID generation.