CHAPTER 5: SETPOINTS 5.4 PROTECTION ELEMENTS
GEK-106310-AF F650 DIGITAL BAY CONTROLLER 5-93
Power Pickup Delay: This setting defines a definite time delay before the inverse time characteristic is activated. If the
curve selection is set as “Definite Time”, the element would operate after this security time delay.
Curve: This setting allows choosing one of three methods to delay operate signal once all conditions are
met to discriminate fault direction:
Definite time: Fixed time delay defined by the POWER PICKUP DELAY setting
Inverse time: Inverse time characteristics delay defined by:
where m is a multiplier defined by the MULTIPLIER setting, S
PKP
is the pickup setting and
S
OP
is the operating power at the time.
FlexCurve A,B,C,D: any time characteristics programmed by the user with FlexCurves.
Multiplier: Time dial multiplier
Snapshot Events: The snapshot event setting enables or disables the snapshot event generation for the wattmetric
ground fault elements.
Element description
The operating power is calculated as:
S_op= real(Vn(In 1ÐMTA)*)
where: * stands for complex conjugate. By varying the MTA angle one can make the element to respond to forward or
reverse direction in inductive, resistive, or capacitive networks as shown in the figure below.
To Next Page