ABB RET670 Applications Manual

( )
( )
( ) ( )
2
0
2 2
Re
Re 1
Re Im
m
U
A X
K
A A
×
= +
+
é ù é ù
ë û ë û
EQUATION1287 V2 EN (Equation 213)
The imaginary component of the same factor is equal to equation 214.
( )
( )
( ) ( )
2
0
2 2
Im
Im
Re Im
m
U
A X
K
A A
×
=
+
é ù é ù
ë û ë û
EQUATION1288 V2 EN (Equation 214)
Ensure that the underreaching zones from both line ends will overlap a sufficient
amount (at least 10%) in the middle of the protected circuit.
Tapped line application
A
B
Z<
Z<
Z<
C
T
IC
IA
IB
-IB
en05000224.vsd
DOCUMENT11524-IMG869 V1 EN
Figure 136: Example of tapped line with Auto transformer
This application gives rise to similar problem that was highlighted in section "Fault
infeed from remote end" that is, increased measured impedance due to fault current
Section 3 1MRK504116-UUS C
IED application
296
Application 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