Deployment of electric vehicles in an adaptive protection technique for riding through cyber attack threats in microgrids

The fault current level is different in grid connected and islanded microgrid fault cases for the same relay due to large integration of distributed energy resources in the latter. Therefore, protection systems must be adaptive and assisted with extensive communication networks to respond to the dynamic changes in the microgrid configurations. However, the microgrid must be protected even under the conditions of a cyber-attack which will render the communication link insecure or down. This paper proposes an adaptive protection scheme abiding by IEC 61850 communication standard for microgrids making them capable of riding-through communication failures by the aid of Electric Vehicle Parks. The control of the Electric Vehicle Park can identify a fault in the AC side based on direct measurements of frequency and voltage without the need for a communication signal. The most critical case is when the microgrid is islanded and the communication is down. In this case, the control will adjust the operation of the connected Electric Vehicles to inject a high current into the microgrid as demanded by the fault, allowing the relays to operate properly. The effectiveness of the proposed protection scheme is evaluated through detailed simulation. The results demonstrate the successful operation of the protective devices during the various modes of operation.