GE T60 Instruction Manual page 487

6 ACTUAL VALUES 6.3 METERING
The tracking frequency is displayed here. The frequency is tracked based on the selection of the reference source with the
setting in the   menu. Refer to the
FREQUENCY AND PHASE REFERENCE SETTINGS SYSTEM SETUP POWER SYSTEM
Power System section of chapter 5 for additional details.
6
GE Multilin T60 Transformer Protection System 6-23