Skip to content
Lightning strikes at night in distance of rural Midwest town

Event Analysis

Home / Program Areas / Reliability Analysis / Event Analysis

MRO is committed to its mission to identify, prioritize and assure effective and efficient mitigation of risks to the reliability and security of the North American bulk power system by promoting Highly Effective Reliability Organizations® (HEROs). ​​In coordination with the ERO Enterprise (collectively NERC and the Regional Entities) and affected registered entities, MRO evaluates bulk power system events to determine root causes, appropriate corrective actions, and lessons learned that can be shared with industry to prevent recurrence. A bulk power system event can be described as an unexpected disturbance to the power grid that leads to a loss of generation or load to a defined number of affected customers.  

Data and information collected during event analyses helps MRO identify trends related to existing and emerging risks to reliability of the regional bulk power system. MRO uses this information to help support changes to the standards and requirements, and to determine what outreach is needed to help registered entities become more aware of, and reduce risk to, their individual systems.

The Event Analysis Process

Event analysis is a collaborative process between MRO and the affected registered entity to identify what happened, why it happened, and what can be done to prevent recurrence. The MRO Event Analysis Process document was created to assist registered entities with understanding the roles and responsibilities pertaining to reporting, assessing, and mitigating system events. This document supports the ERO Enterprise Event Analysis Program.

As part of the event analysis process, each event is assigned a category based on the type of event and its impact on the bulk power system. For more significant events, including all Category 2 or higher, a root cause analysis is performed by the registered entity(s), NERC and MRO, resulting in the assignment of cause codes. Cause codes are characteristics and attributes assigned to similar events to identify trends.

Events in the MRO region should be reported to: [email protected]. If reporting outside of business hours, please call 651.734.8355.

Need more information?

Questions regarding event analysis should be directed to [email protected].