Optimal FCL Placement and Sizing Incorporate DOCR Settings to mitigate Escalated Fault Stresses in Distribution Network

Abstract

Despite providing increased reliability and power quality in meeting the energy demand based on continuous network growth, the high penetration of integrated distributed generations (DGs) has changed the fault current levels and direction. Consequently, some buses are exposed to critical conditions, violate the circuit breakers (CB) handling capacity, and affect the relay coordination operation. Considering this, the distribution network operators inhibit the connection of DGs at high-fault buses to avoid the adverse impact on the switch gears. To mitigate these adverse impacts, fault current limiters (FCL) can be a potential solution. Due to its expensive cost, it is crucial to ensure optimal FCL placement and sizing while maintaining the effectiveness of the protective relay performance during network operations. This paper proposes a combined optimization strategy for optimal deployment and sizing of FCL along with DOCR settings to mitigate the negative impact of DGs in maintaining proper protective device coordination. The proposed combined optimization technique is tested on a Canadian radial Distribution Network (DN). The results show the effectiveness in optimizing the FCL size with the least cost and reducing the overall relay operating time under different grid operating scenarios (On/Off).