Which step is most appropriate if a system disturbance causes a BA to lose frequency meters?

In the context of managing system disturbances, particularly when a Balancing Area (BA) loses frequency meters, placing generating units on standalone operation is a strategic response. This approach maintains system stability by ensuring that the generating units can operate independently from the grid, thereby protecting them from potential fluctuations or instabilities that might arise due to the loss of monitoring equipment.

When frequency meters are lost, the immediate challenge is to manage and stabilize frequency without real-time feedback. By transitioning generating units to standalone operation, operators can manually adjust generation to meet local load needs, rather than relying on potentially outdated or inaccurate data that would come from centralized frequency measurements. This autonomy in operation allows for tailored response strategies that can be adapted based on ongoing conditions, rather than a potentially problematic reliance on external frequency feedback.

Other options, while related to frequency and operational control, do not directly address the immediate concern of losing frequency meters. For example, implementing a frequency bias mode or adjusting settings for tie-line flow would still hinge on having reliable frequency data to base decisions upon, which would not be feasible when the meters are lost. Similarly, switching to flat frequency control may not provide the necessary flexibility or responsiveness needed in a situation where the monitoring of frequency for real-time adjustments is compromised.