Effect of protection device coordination on voltage sag characteristics of distribution networks

In this paper, ATP (a powerful software for simulation of power system transients) is used to assess the performance of a test distribution network in faulty conditions. This study includes the modeling of a distribution network considering the random nature of faults. Fault parameters are produced using a Monte Carlo procedure and initiated before network simulation. To investigate the voltage sag characteristics of the network in faulty conditions, four strategies are introduced for coordination of protective devices. Simulation results are employed to study the network behavior under these protection strategies for fault durations of 200 ms, 600 ms and 1 s. The results are analyzed and compared with ITIC curves where fuses and reclosers are used as protection devices. Simulation results show that protection device coordination has a significant effect on voltage sag characteristics of distribution systems.