BAL-001-TRE-2

R6 · Governor deadband and droop

What it means. Unless the Balancing Authority directs otherwise, the Generator Owner limits Governor deadband to ±0.034 Hz for steam and hydro turbines with mechanical Governors and ±0.017 Hz for all other generating units/generating facilities, and limits droop to the Table 6.2 values, which include 5 percent for Variable Renewable (Non-Hydro), 4 percent for combustion turbines in combined cycle and 5 percent for the other listed types. For digital and electronic Governors, once frequency deviation exceeds the deadband from 60.000 Hz, the Governor follows the droop slope given by the formula in R6.3. Setting an electronic or digital Governor to step into the droop curve is listed as a Severe violation. R6.1 to R6.3 do not apply to steam turbines of a combined cycle resource.

Evidence an auditor expects. Governor test reports, Governor setting sheets and performance monitoring reports (the examples in M6).

R7 and R8 · Governor in service

What it means. The Generator Owner operates each generating unit/generating facility connected to the interconnected transmission system with the Governor in service and responsive to frequency when it is online and released for dispatch, unless it has a valid reason and the Generator Operator has been notified that the Governor is not in service. The Generator Operator notifies the Balancing Authority as soon as practical, and within 30 minutes, of discovering a change in Governor status.

Evidence an auditor expects. Operator logs, voice logs or electronic communications showing each notification and its time.

R9 · Initial Primary Frequency Response

What it means. Each generating unit/generating facility meets a minimum 12-month rolling average initial Primary Frequency Response performance of 0.75, based on participation in at least eight FMEs (otherwise a rolling eight-FME average). Performance is the ratio of Actual to Expected Primary Frequency Response in the initial measurement period, 20 to 52 seconds after the FME starts. The Balancing Authority may exclude an FME for a legitimate operating condition that prevented normal response, such as a data telemetry failure. Under the Primary Frequency Response Reference Document, a resource is not evaluated for an FME if, when the FME occurs, it is operating within a margin of its applicable operating limit; the margin is 2 percent of its High Sustained Limit (HSL) less power augmentation capacity, or 5 MW, whichever is greater. For a wind plant, the Capacity used is its real-time HSL at the time of the FME.

Evidence an auditor expects. Evidence that each resource achieved a rolling average of at least 0.75, and documented evidence of any FME excluded from the average (M9).

R10 · Sustained Primary Frequency Response

What it means. The same 0.75 minimum 12-month rolling average applies to sustained performance, which compares the best actual response between 46 and 60 seconds after the FME starts with the expected response based on system frequency 46 seconds after the start. The eight-FME minimum and the exclusion rule are the same as R9.

Evidence an auditor expects. Evidence that each resource achieved a rolling average sustained performance of at least 0.75, and documented evidence of any excluded FME (M10).

R1 to R5 · Balancing Authority duties

What it means. The Balancing Authority identifies FMEs and, within 14 calendar days, notifies the Compliance Enforcement Authority and publishes the event information. Each month it calculates the 12-month rolling average initial and sustained performance of every generating unit/generating facility, submits the results to the Compliance Enforcement Authority and makes them available to the Generator Owner by the end of the month. Each December it sets the Interconnection minimum Frequency Response (IMFR) for the next year, and if the six-FME rolling average falls below the IMFR it directs actions to improve Frequency Response, which may include directing Governor deadband or droop adjustments.

Evidence an auditor expects. For the Balancing Authority: FME notifications and publications, monthly performance reports, IMFR determinations, and records of actions directed. Generator Owners keep the monthly performance results the Balancing Authority provides as the basis for their R9 and R10 evidence.

For inverter-based plants

BAL-001-TRE-2 covers all generating units/generating facilities in ERCOT, not only inverter-based resources. For inverter-based plants the relevant rows are the ±0.017 Hz deadband for all other generating units/generating facilities and the 5 percent droop for Variable Renewable (Non-Hydro). The standard uses the term Governor and does not define a separate inverter-based equivalent. Battery energy storage is not named in the version 2 tables; the draft BAL-001-TRE-3 adds it to the resource examples in its Background.