Voltage Sags Assessment in Distribution Systems Using Distributed Generation

In distribution systems the most critical disturbance is the interruption of the power service. However, the main concern for end-users is the mal-operation produced by voltage sags.  The presence of distributed generation (DG) modifies the radial configuration of distribution systems and imposes new challenges to be evaluated concerning to the assessment of voltage stability, the performance of protection system, the active power generation and consequently the behavior of voltage sags. This paper shows the influence on voltage sag characteristics by the presence of DG in the IEEE-13 bus test feeder. The analysis is performed by using a random generation of disturbances using a MATLAB routine and simulated in ATP/EMTP software tool. Several case studies in the test system taking into account different locations and sizes of DG unit are presented.