6–112
350 FEEDER PROTECTION SYSTEM – INSTRUCTION MANUAL
S3 PROTECTION
CHAPTER 6: SETPOINTS
Figure 6-50: Volts-per-hertz curves, inverse curve B
Inverse Curve C:
The curve for the Volts/Hertz Inverse Curve C shape is derived from the formula:
where:
T = Operating Time
TDM = Time Delay Multiplier (delay in seconds)
V = fundamental RMS value of voltage
F = frequency of voltage signal
Pickup = volts-per-hertz pickup setpoint