ABB RET670 Commissioning Manual

To verify zone 2 and zone 3 mho characteristic, at least two points must be tested. The
default measuring loop selected is maximum current phase to current loop. Hence the
below characteristics are tested with phase–to-ground fault conditions.
P1
P3
P4
X
R
LineAngle
ZxFwd
ZxRev
P2
IEC11000313-1-en.vsd
IEC11000313 V2 EN
Figure 43: Proposed four test points for phase-to-earth fault
Where,
ZxFwd
is the forward positive sequence impedance setting for zone x (where, x is 2- 3
depending on the zone selected)
ZxRev is the reverse positive sequence impedance setting for zone x (where x is 2- 3
depending on the zone selected)
LineAngle is the Impedance angle for phase-to-phase fault in degrees
Test points X R
P1 ZxFwd · sin( LineAngle ) ZxFwd · cos( LineAngle )
P2 (( ZxFwd - ZxRev / 2) · sin( LineAngle )) ZxFwd / 2 · (1 + cos( LineAngle ) + ZxRev /2 ·
(1 – cos( LineAngle ))
P3 (( ZxFwd - ZxRev / 2) · sin( LineAngle )) - ZxFwd / 2 · (1 – cos( LineAngle ) + ZxRev / 2
· (1 + cos( LineAngle ))
P4 - ZxRev · sin( LineAngle ) - ZxRev · cos( LineAngle )
1MRK 504 165-UUS - Section 11
Testing functionality by secondary injection
Transformer protection RET670 2.2 ANSI 175
Commissioning manual

ABB RET670 Specifications

General

Rated Frequency	50/60 Hz
Inputs	Analog and binary inputs
Application	Protection of power systems
Communication Protocols	IEC 61850, DNP3, Modbus
Operating Temperature Range	-25°C to +55°C
Mounting	Rack mounted
Number of Binary Inputs	Up to 48
Number of Binary Outputs	32
Protection Functions	Overcurrent Protection
Outputs	Binary outputs
Enclosure	IP 54
Type	Line Differential Protection
Number of Analog Inputs	24