GE G60 Instruction Manual page 530

GROUPED ELEMENTS CHAPTER 5: SETTINGS
— This setting enables and disables the field current fault element.
FIELD CURRENT FUNCTION
— This setting selects the DCmA input to be used for the field current protection element. A DCmA
FIELD CURRENT ORIGIN
input can be selected from up to 24 possible inputs, depending on the number of installed transducer modules. In a
HardFiber Brick / G60 system, this setting can point to one of the Resistance Temperature Detector (RTD) inputs mapped to
a Brick DCmA input. In both cases, the minimum and maximum scaling settings of that transducer input are used to
perform the per-unit conversion. The unit setting is configured as "Amps" if the transducer input is used.
These minimum and maximum settings are set as per the Hall sensor current rating. The per-unit computation is scaled to
a base equal to the maximum value setting, with a zero per-unit value corresponding to zero in the unit system used by the
maximum value setting. For example, in the case where the maximum value setting is 100 A, a trip level of 75 A is achieved
by setting the operate level at 0.75 pu, regardless of the range (for example, 4 to 20 mA, 0 to 20 mA, and so on) and
regardless of the minimum value setting.
— Specifies the field current level (in per-unit values) above which the overcurrent element
FIELD OVER CURRENT PICKUP
picks up.
— Specifies a time delay for the overcurrent element. This delay is added to the operating time
FIELD OVER CURRENT DELAY
of the element to obtain the overall delay.
— Specifies the field current level above which the undercurrent element picks up.
FIELD UNDER CURRENT PICKUP
— Specifies a time delay for the undercurrent element. This delay is added to the operating
FIELD UNDER CURRENT DELAY
time of the element to obtain the overall delay.
— Assertion of the FlexLogic operand assigned to this setting blocks operation of the field current
FIELD CURRENT BLK
ground element.
— This setting defines the operation of the field current ground target message. When set to
FIELD CURRENT TARGET
"Disabled", no target message or illumination of a faceplate LED indicator is issued upon operation of the element. When
5 set to "Self-Reset", the target message and LED indication follow the operate state of the element, and self-resets once the
operate element condition clears. When set to "Latched", the target message and LED indication remains visible after the
element output returns to logic 0 until a reset command is received by the relay.
— This setting enables and disables the logging of field current ground events in the sequence of
FIELD CURRENT EVENTS
events recorder.
Figure 5-183: Field current fault detector function logic
5-316 G60 GENERATOR PROTECTION SYSTEM – INSTRUCTION MANUAL