How often do NERC Reliability Standards require a BA to perform control error checks using tie-line MWh meters?

The requirement for Balancing Authorities (BAs) to perform control error checks using tie-line MWh meters at least once per hour aligns with the operational standards set by NERC to ensure reliability in the electric grid. This regular interval allows BAs to monitor and confirm the accuracy of their load forecasting and resource allocations against actual tie-line measurements effectively.

Performing checks every hour helps to detect discrepancies in real-time, which is crucial for maintaining system stability and reliability. If control errors persist or go uncorrected for longer periods, it could lead to larger operational issues and affect the balance of supply and demand. Additionally, this hourly monitoring ensures that BAs can quickly respond to any anomalies, thus supporting the overall reliability of the interconnected grid.

The other frequencies specified in the choices, such as every 10 minutes, at least once per day, or at least once per week, would either not provide sufficient oversight or could lead to delayed responses to potential issues. Thus, the requirement for hourly checks is a proactive measure to uphold the standards of reliability in electric power systems.