ABB Relion 670 Series Technical Reference Manual page 414

Section 7
Current protection
0.6
X
IDirPU
X
0.4
polMethod=Voltage
polMethod=Dual
polMethod=Current
BLOCK
ANSI07000067 V4 EN
Figure 208: Simplified logic diagram for directional supervision element with integrated directional comparison step
7.4.2.8
408
|
|
IopDir
a
a>b
b
a
a>b
b
OR
OR
IPol
T
0.0
F
RNPol
X
Complex
Number
XNPol
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 HarmRestrainx. 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) then
2NDHARMD function output signal is set to logical 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:
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
1MRK505222-UUS C
PUREV
PUFW
FWD
AND FORWARD_Int
AND
REVERSE_Int
RVS
OR
AND
ANSI07000067-4-en.vsd
Technical reference manual