Seyed Hamid Abbasnia - Department of Electrical Engineering, Lahijan Branch, Islamic Azad University, Lahijan, Iran
Hossein Mahdinia Roudsari - Department of Electrical Engineering, Lahijan Branch, Islamic Azad University, Lahijan, Iran
Seyedeh Fatemeh Mousavi - Department Environmental Engineering - Water and Sewage, Science and Research Branch, Islamic Azad University,Tehran, Iran

Increasing penetration of dispersed generation (DG) units in power distribution systems maycause maloperation of coordinated over-current relays; and consequently deteriorating the desirablelevel of reliability and power quality. Re-setting of the protection relays for the new configurationwith DGs is time consuming and inefficient; therefore, maintaining the protection coordination ofdistribution network with presence of DG without handling original setting of protection relays isnoteworthy. More DG penetration lead to more increment in short circuit level of the distributionsystem. Superconducting fault current limiter (SFCL) has been presented to moderate the circuitbreaker’s burden. On the other hand, the SFCLs are known as an effective way to preserve the relaycoordination in presence of DG units. In this paper, an adaptive SCFCL is proposed to preserveprotection coordination of distribution system in presence of DG without handling of originalsetting of protection relays. In the proposed scheme, SFCL is connected in series with each DGunits in the network and its impedance is adjusted by an algorithm to adaptively control the faultcurrent level. In addition the proposed algorithm is regulated in a way to keep the network inislanded operation safe and reliable. The proposed approach is tested and verified on the IEEE 34distribution system in DIGSILENT and the results show the integrity of the proposed scheme.

Protection coordination, distributed generation, adaptive superconducting fault current limiter, relay, distribution network