Real-Time Grid Assessment Is Adequate But Could Be Improved: FERC-NERC Report

Operators of the bulk power system are prepared to manage  assessment of real-time grid operating conditions, but they should develop alternative procedures in the event of data loss failures lasting more than two hours, according to a report issued last week by the staff of the Federal Energy Regulatory Commission (FERC) and the North American Electric Reliability Corporation (NERC) and its regional entities.

Real-time assessment requirements in NERC standards mandate that transmission operators and reliability coordinators perform an assessment at least once every 30 minutes to ensure prevention of instability, uncontrolled separation, or cascading outages that could adversely impact the reliability of the interconnection.  The report detailed these requirements and provided further recommendations for real-time assessments of grid operating conditions.

NERC developed the existing standard requirements in the wake of the 2011 Southwest blackout report to ensure that real‐time tools are adequate, operational, and used frequently enough to provide system operators with the situational awareness needed to identify and plan for contingencies and to reliably operate their systems.

Among the primary causes of the 2003 Northeast blackout was the failure to assess and understand the real-time risks to the grid. The current real-time assessment requirements are a direct result of that finding, NERC says.

The real-time assessment review was not a compliance activity. It included on-site discussions with representatives of nine participating reliability coordinators and transmission operators. The purpose of the review was to work with subject matter expert participants and technology leaders in a collegial environment. The underlying intent, according to the report, was that understanding operational challenges enhances regulatory oversight.

Among other findings, the report found that as the penetration of renewable generation and inverter-based resources increases, transmission system operators should be prepared to augment existing tools to facilitate reliable operation planning that includes renewable forecasting.

Among other recommendations, the report said reliability coordinators and transmission operators should:

• revisit their real-time assessment procedures to ensure that clear instructions are given for what information should be included in the human evaluation component of the real-time assessment;
• study and identify all pertinent sub-transmission facilities that are impactful and external facilities for real-time monitoring and contingency analysis; and
• add the pipelines supplying that generation to their map-based displays showing associated generating stations and have real-time availability status data for the pipelines integrated into those displays (for those coordinators and operators with a high concentration of natural gas generation).  

The review team also found that all participants have processes for identifying problems with quality of individual real-time data points and have procedures for correcting the errors.

However, only a few of the participants have developed metrics to trend aggregate real-time data errors with thresholds identifying when errors are reaching levels that would impair the quality of the real-time assessment, the report found.