Impact of distributed generation on network short circuit level

Distributed generation (DG) technology is spreading rapidly owing to advantages of clean environment, loss reduction and voltage improvement. Utilities in Pakistan are welcoming all generations to increase their supply capacity. Industries are installing DGs to meet their load requirements. In order to reduce energy bills, DGs are being used to supply spare power back to utility or even in off peak durations. DG interconnection changes electrical network characteristics of existing utility network. Protection problems may occur in the form of relay settings, islanding and increased short circuit currents. This paper investigates the effects of DG interconnection on short circuit currents. A feeder of SITE industrial area of Karachi is modeled and simulated for short circuit analysis. Analysis shows that DG interconnection to a radial feeder increases short circuit level at all nodes of the feeder.