ABB RELION RET670 User Manual

9.2.3.2 Setting example
GUID-20729467-24AB-42F0-9FD1-D2959028732E v1
Directional phase overcurrent protection, four steps can be used in different ways,
depending on the application where the protection is used. A general description is
given below
.
The pickup current setting of the inverse time protection, or the lowest current step of
the definite time protection, must be defined so that the highest possible load current
does not cause protection operation. The protection reset current must also be
considered so that a short peak of overcurrent does not cause the operation of a
protection even when the overcurrent has ceased. This phenomenon is described in
Figure
262.
Pickup current
Current I
The IED does not reset
Line phase current
Time t
Reset current
ANSI09000146-en-1.vsd
ANSI09000146 V1 EN-US
Figure 262: Pickup and reset current for an overcurrent protection
The lowest setting value can be written according to Equation
422.
Section 9 1MRK 504 163-UUS A
Current protection
526 Transformer protection RET670 2.2 ANSI
Application manual

ABB RELION RET670 Specifications

General

Rated Frequency	50/60 Hz
Communication Protocols	IEC 61850, IEC 60870-5-103, DNP3
Operating Temperature Range	-25°C to +55°C
Mounting	Rack Mounting
Input Voltage	100-240 V AC
Protection Functions	Overcurrent Protection
Enclosure	IP20