Which solution is most effective for voltage control during the re-energization of a transmission system?

The most effective solution for voltage control during the re-energization of a transmission system is the use of local load adjustments and Ultra-High Voltage Transformer (ULTC) transformers. This approach allows for precise management of voltage levels by adjusting the transformer taps in response to real-time system conditions. ULTC transformers can automatically or manually adjust their voltage output to maintain stable voltage profiles in the system, which is critical during re-energization when loads may fluctuate significantly.

Local load adjustments also play a significant role; by managing local loads, operators can balance supply and demand more effectively at specific locations within the system. This proactive approach helps to prevent voltage instability, which is crucial when reconnecting generation resources and restoring service to affected areas.

In contrast, shutting down all non-essential power loads may reduce the overall demand temporarily but does not provide a robust solution for voltage regulation as the grid begins to stabilize. Increased reliance on renewable energy sources can introduce variability into the system, which may not be as beneficial for voltage control during the sensitive re-energization phase. Waiting for full-system recovery fails to address immediate voltage control needs and may lead to further instability as the system attempts to stabilize without active management of local voltages and loads.