Power System Frequency - GE D90 Plus Instruction Manual

CHAPTER 7: PROTECTION

Power system frequency

PLUS
D90 LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
Figure 107: Typical power system settings
We have:
• CT primary =
Phase CT Ratio
• VT primary =
Phase VT Ratio
The power cut-off is therefore:
Any calculated power value below this cut-off will not be displayed. As well, the three-
phase energy data will not accumulate if the total power from all three phases does not
exceed the power cut-off.
Select the Settings > Protection > Power System > Frequency menu item to open the
power system frequency configuration window.
Figure 108: System frequency configuration settings
The following settings are available.
× = 20 × 5 A = 100 A.
Phase CT Secondary
× = 208 × 66.4 V = 13811.2 V.
Phase VT Secondary
POWER SYSTEM
Eq. 7
143