Meeting Frequency Response Requirements (BAL-003-1)
NERC’s Frequency Response and Frequency Bias Setting standard (BAL-003-1) has an enforcement date of April 1, 2015. During this implementation period, a number of Balancing Authorities (BA) have used NERC’s FRS Form 1 to determine where they are relative to the requirements. The form is populated with 2013 frequency events and BA specific information calculated from the previous year’s FERC-714 filing. The BA can then populate with Interchange and load data using FRS Form 2. The results of Form 1 are transferred to Form 2, which compares the BA’s Frequency Responsive Objective (FRO) with the Frequency Responsive Measurement (FRM) for each event. This result determines if the requirement to assist with frequency events in the interconnection has been met. The FRO is calculated by NERC using the previous year’s data and the FRM is calculated using the delta frequency, delta load and delta interchange data during the period of T+20 to T+52 seconds after the frequency event. If the FRM is not more negative than the FRO, there is a shortcoming.
If for a particular event, the FRM is not more negative than the FRO, there are a number of scenarios that can explain the shortfall.
- Are there unaccounted for pseudo tie line values in the interchange numbers entered on FRS Form 2?
- Were any generators being ramped offline during the event?
- Were there any generator trips during the event?
- Were there any non-conforming loads that changed drastically during the event?
FRS Form 2 allows for lost generation or increased load before and after the event.
To analyze further potential issues, we need to investigate how the fleet of generators in the Balancing Area performs to the frequency excursion. Such a study will demonstrate a number of issues such as:
- Was the frequency reserve too low due to limited online units or online units running close to peak load?
- Are there generators in the fleet whose governors are not responding, responding too slow or going in the wrong direction?
Performing such a study during successful events will provide potential improvements to further ensure successful response to frequency events in neighboring Balancing Areas.
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