ABB Relion 650 Series Applications Manual page 36

Section 3
REB650 setting examples
Item
CT rated symmetrical short-circuit
current factor K
CT secondary winding resistance
0
75 C
145 kV VT ratio
The high impedance differential protection needs dedicated CTs which have identical turns ratio
and similar magnetizing characteristics. Class TPS CTs, according to IEC 60044-6, and class PX
CTs, according to IEC 60044-1, are usually selected for this application. The class TPS CTs are used
in the following example.
Table 3:
Item
Secondary CT conductor cross section
area
Maximum length between bay and
protection
The following protection functions are available:
30
ssc
R
at
ct
CT secondary wiring data
Only settings that need adjustment due to the specific application are described in
setting examples. It is recommended to keep the default values for all settings that
are not described. Refer to Technical manual for setting tables for each protection
and control function.
For the functions not explained in the setting examples section, refer to the
Setting guidelines section of the corresponding function.
Use parameter setting tool in PCM600 to set the IED according to calculations for
the particular application.
© Copyright 2013 ABB. All rights reserved
Data
20
5 Ω
The rated equivalent secondary e.m.f. E
(
= × × +
E I K R R
al NS ssc ct
where I is the rated secondary current of the CT
NS
145 0.11 0.11
/ / kV
3 3 3
Data
2
2.5 mm
150 m
This gives the maximum secondary conductor resistance:
( )
( )
l m
2
r
= W × ×
R mm / m
( )
sec
A mm
2
ϱCU = 0,0172 (Ω·mm /m) at 20
2
ϱCU = 0,021 (Ω·mm /m) at 75
R = 0,021 * 150 / 2,5 = 1,26 Ohm
sec
1MRK 505 287-UUS B
can now be calculated:
al
) ( )
= × × + =
1 20 5 25 600 V
b
2
°
C
°
C
Busbar protection REB650
Application manual