CHAPTER 5: SETPOINTS 5.4 PROTECTION ELEMENTS
GEK-106310-AF F650 DIGITAL BAY CONTROLLER 5-75
Operation of the Ground directional element 67G is similar to the operation of the neutral directional element 67N (refer to
section 5.4.4.3 Neutral directional element (67N)), with the exception that the operation magnitude here is the ground
current Ig (67G), measured from the input terminals B9-B10 instead of the Neutral current, In (67N), calculated from the
phase currents.
Polarization magnitudes can be, as in the case of 67N, Polarization voltage (3Vo), either calculated from the phase voltages
or measured from terminals A11-A12, or polarization current (Ip), measured from the fifth input transformer terminals, Isg,
terminals B11-B12.
The following table shows the used magnitudes in each of the Polarization possibilities:
Table 5-45: Magnitudes according to polarization setting
The following table shows the management of the element output signals (block and permission) depending on the
Polarization Type setting.
Table 5-46: Output signal management according to polarization type setting
The configuration of the signals required for blocking the Ground overcurrent elements from the signals provided by the
Ground directional element is made at Setpoint > Relay Configuration > Protection Elements using inverted operation
signals to block the trip.
For example, to block the ground time delayed elements:
GROUND TOC1 BLOCK = NOT (GROUND DIR1 OP)
GROUND TOC2 BLOCK = NOT (GROUND DIR2 OP)
GROUND TOC3 BLOCK = NOT (GROUND DIR3 OP)
To block the Ground Instantaneous elements:
GROUND IOC1 BLOCK = NOT (GROUND DIR1 OP)
GROUND IOC2 BLOCK = NOT (GROUND DIR2 OP)
GROUND IOC3 BLOCK = NOT (GROUND DIR3 OP)
POLARIZATION setting OPERATION MAG. POLARIZATION MAG.
Vo Ig 3V0
Ip Ig Isg
Vo + Ip Ig 3V0 or Isg
Vo * Ip Ig 3V0 and Isg
POLARIZATION setting GROUND DIR BLOCK SIGNAL GROUND DIR OP SIGNAL
Vo V
0
< Ajs. POL V THRESHOLD Permission V
0
Ip I
P
< 5 mA Permission I
P
Vo + Ip V
0
< POL V THRESHOLD
I
P
< 5 mA
Permission V
0
Permission I
P
Vo * Ip V
0
< POL V THRESHOLD
I
P
< 5 mA
Permission V
0
Permission I
P
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