ABB Relion 650 Series Technical Manual page 234

Section 6
Current protection
6.16 Negative sequence based overcurrent function DNSPTOC
(46)
6.16.1 Identification
Function description
Negative sequence based
overcurrent function
6.16.2 Functionality
Negative sequence based overcurrent function (DNSPTOC, 46) may be used in power line
applications where the reverse zero sequence source is weak or open, the forward source
impedance is strong and it is desired to detect forward ground faults.
Additionally, it is applied in applications on underground cables, where zero sequence impedance
depends on the fault current return paths, but the cable negative sequence impedance is
practically constant.
The directional function is current and voltage polarized. The function can be set to forward,
reverse or non-directional independently for each step.
DNSPTOC (46) protects against all unbalanced faults including phase-to-phase faults. The
minimum pickup current of the function must be set to above the normal system unbalance level
in order to avoid unintentional tripping.
6.16.3 Function block
I3P*
V3P*
BLOCK
BLKOC1
ENMLTOC1
BLKOC2
ENMLTOC2
ANSI09000125 V1 EN-US
Figure 120: DNSPTOC (46) function block
228
DNSPTOC (46)
TRIP
TROC1
TROC2
BFI_3P
PU_OC1
PU_OC2
DIROC1
DIROC2
CURRENT
VOLTAGE
VIANGLE
ANSI09000125-1-en.vsd
© Copyright 2011 ABB Power Grids. All rights reserved
IEC 61850 IEC 60617
identification identification
DNSPTOC
3I2>
IEC09000132 V2 EN-US
1MRK 506 326-UUS B
GUID-66A7DE2F-EBD6-4601-B0F7-2B568968EA33 v1
GUID-F53558B3-4614-4502-82DD-B7BA07FB2723 v1
ANSI/IEEE C37.2
device number
46
GUID-CFD34404-5934-41EE-8AAC-A5FD2B9B4E33 v3
GUID-E93E47F7-E421-420E-BF4B-E66481BA7454 v2
Line distance protection REL650
Technical manual