ABB Relion 650 Series Technical Manual page 183

1MRK 506 326-UUS B
=
V Zo
IPol
EQUATION2013-ANSI V1 EN-US
which will be then used, together with the phasor of the operating current, in order to determine
the direction to the ground fault (Forward/Reverse). In order to enable current polarizing the
magnitude of polarizing current shall be bigger than a minimum level defined by setting
parameter
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
ANSIEQUATION1878 V1 EN-US
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).
6.6.7.3 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 then possible via function binary input BLKn(where x indicates the relevant step
within the protection) 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 based overcurrent function.
6.6.7.4 Base quantities within the protection
The base quantities are entered as global settings for all functions in the IED. Base current (
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.
(
6.6.7.5 Internal ground-fault protection structure
The protection is internally divided into the following parts:
1. Four residual overcurrent steps.
2. Directional supervision element for residual overcurrent steps with integrated directional
comparison step for communication based ground-fault protection schemes (permissive or
blocking).
3. Second harmonic blocking element with additional feature for sealed-in blocking during
switching of parallel transformers.
Each part is described separately in the following sections.
Line distance protection REL650
Technical manual
(
× = + ×
I RNPol j XNPOL
S Pol
IPolMin .
+ = - + ×
VVPol VIPol 3 V Z IPol
0 0 s
© Copyright 2011 ABB Power Grids. All rights reserved
)
×
I
Pol
(
= - + +
3 V RNPol jXNPol
0
)
×
IPol
Section 6
Current protection
(Equation 32)
(Equation 33)
M13941-144 v3
M13941-152 v4
IBase )
M13941-157 v2
177