Presented by Leila Chebbo, Dominion Energy, Senior Engineer
Black start is critical to power system resilience, enabling utilities to recover from blackout events without relying on the external grid. One of the most challenging stages of restoration is island synchronization, during which energized islands must be safely reconnected while maintaining acceptable operating conditions. Although existing guidelines provide general recommendations, several key operational decisions remain insufficiently defined.
This work focuses on identifying best practices for island synchronization during black start, supported by real-time EMT simulation studies using RTDS. A framework for developing largescale RSCAD models of Dominion Energy’s transmission system with real-time Energy Management System (EMS) data is introduced and demonstrated through a case study.
The case study validates synchro-check relay settings across a wide range of operating conditions, identifying parameter thresholds that enable secure breaker closure. Beyond relay setting validation, the study evaluates the island energization level prior to synchronization, examining how generator and load pickup influence system readiness for reconnection. In addition, this work investigates the timing of generator control mode transitions, specifically whether the master generator should switch from isochronous to droop control before or after island synchronization.
The results provide practical guidance for improving synchronization reliability and supporting operator decision-making during system recovery.