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Electrical Transmission Tower with Availability data system in use in Midwest agricultural field

Transmission Availability Data System

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Transmission Availability Data System (TADS)

TADS is a web-based system used to report and collect system inventory and transmission outage data, in a common format. A decision tree is available in the NERC TADS Data Reporting Instructions (page v) that defines what element outages need to be reported in TADS. NERC uses the information available in TADS to develop transmission system metrics that analyze outage frequency, duration, causes, and other factors related to transmission outages. 

Applicable To:

TADS data is mandatory for all NERC-registered U.S. Transmission Owners (TO). Per Section 1600, non-U.S. Transmission Owners on the NERC Compliance Registry are required to provide Non-Automatic outage TADS data. 


Data is collected quarterly.

How To Report:

Data is collected through the NERC OATI webTADS application. The TADS reporting manual is updated annually and is available on the NERC TADS website.

MRO’s Role

MRO staff primarily function as TADS administrators. MRO assists NERC staff in initial registration of users and organizations, as well as overseeing data entry prior to aggregation at the NERC level. At the end of each reporting period, MRO staff ensure that all TADS data forms have been completed by each Functional Entity. Additionally, MRO performs data validation to ensure any flagged content is revised by the end of the regional reporting period. Upon conclusion of the Regional Entity data review, NERC staff will begin their aggregation and review of the reporting period’s data.

Need More Information?

For additional information, refer to the Data Reporting Instructions on the NERC TADS website. If you have a question regarding this data request for MRO please contact [email protected].