GEK-113032A W650 Wind Generator Protection System 5-57
5 SETTINGS 5.4 PROTECTION ELEMENTS
5
5.4.5.3 GROUND DIRECTIONAL ELEMENT (67G)
Ground directional is a directional protection element, used for monitoring the ground overcurrent elements. The operation
magnitude is the ground current measured directly from the corresponding input (B9-B10), while the polarization magnitude
is the neutral voltage (V
n
). The neutral voltage is calculated from the three phase voltages or measured from the dedicated
voltage input (A11-A12).
In case of using the voltage measured from the dedicated voltage input terminals, the Auxiliary Voltage setting in General
settings must be VN.
As in the case of a phase directional element, this element incorporates a voltage loss logic that allows blocking or
permitting the trip by means of a setting
Table 5–53: 67G ELEMENT SETTINGS
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), 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 fith input transformer
terminals, Isg, terminals B11-B12.
The following table shows the used magnitudes in each of the Polarization possibilities:
Table 5–54: USED MAGNITUDES ACCORDING TO THE POLARIZATION SETTING
SETPOINT > PROTECTION ELEMENTS > GROUND CURRENT > GROUND DIRECTIONAL >
GROUND DIRECTIONAL 1> GROUND DIRECTIONAL 2 > GROUND DIRECTIONAL 3
SETTING DESCRIPTION NAME DEFAULT VALUE STEP RANGE
Function permission Function DISABLED N/A [DISABLED – ENABLED]
Maximum Torque Angle MTA -45 1 Deg [-90 : +90]
Operation Direction Direction FORWARD N/A [FORWARD – REVERSE]
Polarization type Polarization VO N/A [V
0
– I
P
– V
0
+I
P
– V
0
*I
P
]
Block logic type Block Logic PERMISSION N/A [BLOCK – PERMISSION]
Polarization voltage threshold Pol V Threshold 50 1 V [0 : 500]
Snapshot event generation Snapshot Events ENABLED N/A [DISABLED – ENABLED]
POLARIZATION SETTING OPERATION MAG. POLARIZATION MAG.
Vo Ig 3V0
Ip Ig Isg
Vo + Ip Ig 3V0 or Isg
Vo * Ip Ig 3V0 and Isg
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