ABB Relion 650 Series Technical Manual page 202

Section 6
Current protection
6.9.1 Identification
Function description
Thermal overload protection, one
time constant
6.9.2 Functionality
The increasing utilizing of the power system closer to the thermal limits has generated a need of a
thermal overload protection also for power lines.
A thermal overload will often not be detected by other protection functions and the introduction
of the thermal overload protection can allow the protected circuit to operate closer to the thermal
limits.
The three-phase current measuring protection has an I
constant and a thermal memory.
An alarm pickup gives early warning to allow operators to take action well before the line is
tripped.
6.9.3 Function block
I3P*
BLOCK
AMBTEMP
SENSFLT
RESET
ANSI08000038 V1 EN-US
Figure 103: LPTTR (26) function block
6.9.4 Signals
196
LPTTR (26)
TRIP
PICKUP
ALARM
LOCKOUT
TEMP
TEMPAMB
TERMLOAD
ANSI08000038-1-en.vsd
LPTTR has no input for external temperature sensor in this release of 650 series.
© Copyright 2011 ABB Power Grids. All rights reserved
IEC 61850 IEC 60617
identification identification
LPTTR
SYMBOL-A V1 EN-US
2
t characteristic with settable time
1MRK 506 326-UUS B
ANSI/IEEE C37.2
device number
26
GUID-1451086D-C24F-49D3-90B4-9D6401E6A2F3 v2
Line distance protection REL650
Technical manual
M17106-1 v4
M12020-4 v7
M12627-3 v5