ABB REQ650 User Manual

Where I
fA
and I
fB
have been described in the previous paragraph. Considering the
safety margins mentioned previously, the minimum setting Is as given in equation
below:
Is ³1.3·Imin
EQUATION83 V2 EN (Equation 13)
The protection function can be used for the specific application only if this setting
value is equal or less than the maximum phase fault current that the IED has to clear.
The IED setting value IP>> is given in percentage of the primary base current value,
IBase. The value for IP>> is given from this formula:
100
Is
IP
IBase
>>= ×
EQUATION1147 V3 EN (Equation 14)
6.3 Four step phase overcurrent protection 3-phase
output OC4PTOC
6.3.1 Identification
Function description
IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Four step phase overcurrent protection
3-phase output
OC4PTOC
4
4
alt
3I>
TOC-REVA V1 EN
51/67
6.3.2 Application
The Four step phase overcurrent protection 3-phase output OC4PTOC is used in
several applications in the power system. Some applications are:
• Short circuit protection of feeders in distribution and subtransmission systems.
Normally these feeders have radial structure.
• Back-up short circuit protection of transmission lines.
• Back-up short circuit protection of power transformers.
• Short circuit protection of different kinds of equipment connected to the power
system such as; shunt capacitor banks, shunt reactors, motors and others.
• Back-up short circuit protection of power generators.
Section 6 1MRK 505 291-UEN A
Current protection
94
Application manual

ABB REQ650 Specifications

General

Brand	ABB
Model	REQ650
Category	Protection Device
Language	English