Blocking Conditions and Optimization Suggestions for Fully Automatic Feeder Automation

Fully automatic feeder automation (FA) can achieve fault isolation and power restoration in non-fault areas within minutes, effectively enhancing the resilience of the power grid. To prevent abnormal operation of fully automatic FA, blocking conditions are typically established in the distribution master station. However, it has been proven in practice that some blocking conditions are overly conservative, potentially prolonging the customer interruption duration (CID) during fault. This paper elaborates on all the blocking conditions of fully automatic FA, with a particular focus on the impacts of terminal offline and discontinuous fault current signals. Through simulation in the dispatcher training system (DTS), it is demonstrated that these two blocking parameters fails to prevent misoperation of fully automatic FA, and shall only increase the number of CID. By removing these two blocking conditions, the success rate of fully automatic FA actions improved from 51% to 90%, as validated by operating data in Wuxi.