TADS GMD Event Reporting Reminder

Following the recent geomagnetic storm on May 10 – May 12, 2024, NERC is asking that all entities carefully review transmission Outages during this time period and consider whether Geomagnetic Disturbances (GMD) may be a cause or a contributing cause of the event. Some examples of how GMD may affect transmission equipment are:

• Unintended protective relay operations due to elevated system harmonics
• Voltage oscillations
• Hot-spot heating in power transformer windings and structural parts
• High reactive power consumption in power transformers
• Increased dissolved combustible gases in power transformer oil
• Unusual noise and vibration in power transformers

Additional information can be found in the TADS Data Reporting Instruction (DRI) and NERC Special Reliability Assessment: Effects of Geomagnetic Disturbances on the Bulk Power System (February 2012).

When reporting the event in the Transmission Availability Data System, we ask that you report any such GMD-related outages by designating the Initiating and/or Sustained Cause Code as Environmental, which encompasses Geomagnetic Storms. Accurate reporting for this event is crucial to assess the impact of this major GMD event.

The Q2 reporting deadline is August 15, 2024. Please direct any reporting questions to tads@nerc.net or gmd@nerc.net. Information on Geomagnetic Disturbance reporting and available data can be found on the NERC website.