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Chapter 3 Paramters/Functions Innovation Series Medium Voltage GP Type - G Drives GEH-6385
Motor Ground Protection
The Motor Ground Protection function detect s a ground fault con dition in the mot or
phases. The function is automatically configured by the control; no user
configuration is necessary.
Function inputs
The following table specifies the input variables of the Motor Ground Protection
function.
Variable Description
DC neut volt mag Absolute value of the DC bus neutral voltage
Function outputs
The following table specifies the output variables of the Motor Ground Protection
function.
Variable Description
Gnd cur signal Ground current indication (filtered). Note that this value may
actually be scaled as the voltage sensed by the BICM, not a
current. If Gnd signal scl is 1.0, this is the sensed voltage.
Gnd flt warning This variable is used external to this function to indicate that the
alarm, Ground flt alm, LP is present.
Gnd flt trip This variable is used external to this function to indicate that the
fault, Gnd flt trip is present.
LP fuse stat This signal, when True, indicates that the value LP fuse blown
sel points to is True. When Detector mode is set to Disable, this
variable will always be True.
Function configuration
The following table specifies the configuration parameters of the Motor Ground
Protection function . The control sets these parameters automatically; they should not
be changed except in unus ual circumstances.
Parameter Description
Detector mode When set to Enable, the Motor Ground Protection function is
enabled. The Ground flt alm, LP alarm and Gnd flt trip trip
fault will be annunciated if a ground fault condition occurs.
When set to Disab le, neither th e alarm nor fault wi ll occur.
The default is Enable.
Gnd signal sel Pointer to the ground fault signal. It points by default to
parameter DC neut volt mag.
Gnd signal scl Voltage to current scale factor which is applied to the input
analog signal pointed to by Gnd signal sel. This parameter is
set to 1.0 as d efault, leavin g the scaled signa l output as a
voltage.
Gnd signal al arm on The lev el at which the Ground flt alm, LP alarm is present.
Gnd signal al arm off The l evel at which th e Ground flt alm, LP alarm clears.
Gnd signal trip lvl The level at which the Gnd flt trip trip fault o ccurs.
Gnd signal fil The bandwidth of the low pass filter (Radians/second) applied
to the analog input signal pointed to by Gnd signal sel.
LP fuse blown sel Pointer default setting is MOV fuse OK status.