External Polarizing For Ground-Fault Function - ABB RES670 Technical Manual

Section 8
Current protection
8.2.7.3
8.2.7.4
8.2.7.5
202
In order to enable current polarizing, the magnitude of the polarizing current shall be
bigger than a minimum level defined by setting parameter IPolMin.
Dual polarizing
When dual polarizing is selected, the function will use the vectorial sum of the voltage
based and current based polarizing in accordance with the following formula:
= + = -
VTotPol VVPol VIPol 3
ANSIEQUATION1878 V1 EN-US
Vpol and Ipol can be either zero sequence component or negative sequence component
depending upon the user selection.
Then the phasor of the total polarizing voltage VTotPol will be used, together with the
phasor of the operating current, to determine the direction of the ground fault (forward/
reverse).

External polarizing for ground-fault function

The individual steps within the protection can be set as non-directional. When this
setting is selected, it is possible via the function binary input BLKx to provide external
directional control (that is, torque control) by, for example, using one of the following
functions if available in the IED:
1. Distance protection directional function.
2. Negative sequence polarized general current and voltage multi purpose protection
function.
Directional detection for ground fault function
Zero sequence components will be used for detecting directionality for the ground fault
function. In some cases, zero sequence quantities might detect directionality
incorrectly. In such a scenario, negative sequence quantities will be used. The user can
select either zero sequence components or negative sequence components for detecting
directionality with the parameter SeqTypeIPol. I3PDIR input is always connected to the
same source as I3P input.
Base quantities within the protection
The base quantities are entered as global settings for all functions in the IED. Base
current (IBase) shall be entered as rated phase current of the protected object in
primary amperes. Base voltage (VBase) shall be entered as rated phase-to-phase
voltage of the protected object in primary kV.
(
+ × = - +
V Z IPol 3 V RNPol
0 0 s 0
1MRK 511 408-UUS A
)
+ ×
jXNPol IPol
GUID-FC382DD3-E2C8-455E-8CD5-1DE1793DD178 v6
Phasor measurement unit RES670 2.2 ANSI
Technical manual
(Equation 20)
M13941-144 v6
M13941-152 v6