Flexcurves - GE D90 Plus Instruction Manual

CHAPTER 7: PROTECTION

FlexCurves™

FlexCurve™ settings
PLUS
D90 LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
Figure 314: Digital counter scheme logic
There are four user-programmable FlexCurves™ available with the D90
A, B, C, and D.
The curve shapes for the four FlexCurves are derived from the following equations.
In the above equations, T
operate
the multiplier setting, I represents the input current, I
pickup current setting, T
flex
represents the reset time in seconds.
Select the Settings > Protection > Control > FlexCurves > FlexCurve A menu item to
access the FlexCurve™ A settings. The same group of settings is available for FlexCurves™
B, C, and D.
represents the operate time in seconds, TDM represents
pickup
represents the FlexCurve™ time in seconds, and T
CONTROL ELEMENTS
Plus
system, labeled
Eq. 40
Eq. 41
represents the value of the
reset
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