Improving Protection Reliability of Multi-source Meshed Power systems by An Automation-assisted Overcurrent Protection

The overcurrent protection of multi-source meshed power systems has been a challenge since their emergence owing to the low fault-current seen by the backup protection. This issue results in reduced protection coverage and consequently protection reliability deficiency. This paper seeks to propose a communication-assisted automated protection scheme which relies on the rapid communication channels of power-line-carrier (PLC) system to improve the protection reliability of power systems. On the other hand, the main overcurrent protection topology stays untouched to avoid further technical complications for system operators. That is, the conventional protection coordination optimization process stays valid for all relay-pairs except for those with lower protection coverage which are the target pairs for the proposed automated PLC-based protection coordination scheme. By this scheme, in the event of a fault, the primary relay communicates with the backup for fault clearing in a proper time. Moreover, the characteristics of the relays are modified to relax the coordination optimization space which results in a better performance of the protection system. The proposed scheme is applied on the IEEE 14-bus testbed and the results are deeply investigated.