ABB REC650 ANSI User Manual

a
b
a>b
OR
|I
OP
|
STx
AND
Pickupx
Characteristx=DefTime
DirMode Selx= Disabled
DirMode Selx= Non-directional
DirModeSelx=Forward
DirModeSelx=Reverse
AND
AND
FORWARD_Int
REVERSE_Int
OR
OR
STAGEx_DIR_Int
ANSI12000008-3-en.vsd
AND
AND
Characteristx=Inverse
I nverse
ANSI12000008-3-en.vsd
0
0-tx
0
0-txMin
PUx
ANSI12000008 V3 EN
Figure 33: Simplified logic diagram for OC4PTOC
6.2.8 Second harmonic blocking element
A harmonic restrain of the Four step overcurrent protection function OC4PTOC 51_67
can be chosen. If the ratio of the 2nd harmonic component in relation to the fundamental
frequency component in the residual current exceeds the preset level defined by parameter
2ndHarmStab setting, any of the four overcurrent stages can be selectively blocked by
parameter HarmRestrainx setting. When 2nd harmonic restraint feature is active, the
OC4PTOC 51_67 function output signal 2NDHARMD will be set to logical value one.
a
b
a>b
BLOCK
AND
I
OP
Extract second
harmonic current
component
Extract
fundamental
current component
X
2ndHarmStab
a
b
a>b
a
b
a>b
0.07*IBase
IEC13000014-1-en.vsd
2
N D
H A R M
D
2ndH_BLOCK_Int
IEC13000014 V1 EN
Figure 34: Second harmonic blocking
Section 6 1MRK 511 287-UUS A
Current protection
94
Technical manual

ABB REC650 ANSI Specifications

General

Brand	ABB
Model	REC650 ANSI
Category	Controller
Language	English