ABB RELION 670 Series Technical Manual page 492

Section 8
Current protection
0.6
X
IDirPU
X
0.4
polMethod=Voltage
polMethod=Dual
polMethod=Current
BLOCK
ANSI07000067 V4 EN-US
Figure 256: Simplified logic diagram for directional supervision element with integrated directional
comparison step
8.4.7.9 Second harmonic blocking element
A harmonic restrain of four step residual overcurrent protection function EF4PTOC can be chosen
for each step by a parameter setting
relation to the fundamental frequency component in the residual current exceeds the preset level
(defined by parameter
value one and harmonic restraining feature to the function block will be applicable.
Blocking from 2nd harmonic element activates if all three criteria are satisfied:
1. Current fundamental frequency component >
2. Current second harmonic component >
3. Ratio of the 2nd harmoinc component in relation to the fundamental frequency component in
the residual current exceeds the preset level defined parameter
If all the above three conditions are fulfilled then ST2NDHRM function output signal is set to
logical value one and harmonic restraining feature to the function block is applicable.
486
| |
IopDir
a
a>b
b
a
a>b
b
OR
OR
IPol
T
0.0
F
RNPol
X
Complex
Number
XNPol
2ndHarmStab ) then ST2NDHRM function output signal is set to logical
AND
REVERSE_Int
AND
FORWARD_Int
AngleRCA
VPolMin
IPolMin
VPol
T
I3PDIR
0.0
F
VTPol
VIPol
STAGE1_DIR_Int
T
STAGE2_DIR_Int
0.0
F
STAGE3_DIR_Int
STAGE4_DIR_Int
HarmRestrainx . If the ratio of the 2nd harmonic component in
IMinOpHarmBlk
IMinOpHarmBlk
1MRK 502 066-UUS B
PUREV
PUFW
FWD
AND FORWARD_Int
AND
REVERSE_Int
RVS
OR
AND
ANSI07000067-4-en.vsd
2ndHarmStab setting
Technical manual
M13941-200 v6