چكيده به لاتين
Abstract:
Nowadays, the installation and operation of DGs is increasing in power systems due to its benefits including loss reduction, peak shaving, ancillary services, higher power quality, their shorter build time, the lower loss of load probability as well as the deferral of transmission, distribution replacement, deregulation issues, and environmental concerns. Currently, the vast majority of these resources are small scale SGs (SSSGs). Therefore, in this thesis it focuses on these types of DG resources. SSSGs mostly installed in distribution networks and they are protected by overcurrent relays. Installing SSSGs raises problems in the coordination of distributed network relays and also significantly increases the fault rate. The most important point to be considered, due to the inertia constant of small scale SGs and the longer clearing fault time in distribution network compared with transmission networks, the probability of unstable SSSGs is far higher than power generators. So this should be taken into account when setting up relays. On the other hand, the huge disconnection of DGs in the fault of network causes a significant loss of load and reduced network reliability. Saturated Iron Core Superconducting Fault Current Limiter (SISFCL) is considered as an appropriate solution to solve the problem of connecting DGs. Due to the asymmetric structure of SISFCL, modeling is carried out at finite element (COMOL-3D). And for the direct connection of the finite element with the powerful DIGSILENT software, a method is suggested. The main objective of this project is to achieve the optimized structure of SISFCL in a way that can prevent unsustainability in SSSGs, the fault current is reduced to an acceptable level and consequently, it eliminates lack of coordination between over current relays in the presence of SSSGs. Also, by connecting SISFCL over the SSSG connection to the network, the network can improve the possibility of the fault. The results of this study can be generalized to the other SFCLs. it is necessary to mention, due to the applicability of the research, focus has been on the existing Iranian distribution network.
Keywords: finite element method, saturated iron core superconducting fault current limiter, transient stability.
