Increasing the penetration level of distributed generation without violating overcurrent based protection system coordination

The interconnection of distributed generators (DGs) into distribution systems causes several adverse effects to the overcurrent based protection system coordination. These adverse effects are loss of coordination, loss of sensitivity, bi-directionality of protection devices, fuse nuisance blowing, and temporary overvoltage. This paper provides general guidelines about the maximum penetration of DG that can be connected to suburban feeders without causing the aforementioned protection system adverse effects. To perform this study, field data for two suburban distribution feeders provided by local distribution company were modeled using CYMDIST software. Different types of DGs were modeled and aggregated with the feeders under study in order to evaluate the maximum permissible limits of DG penetration.