Thermal Overload Protection, One Time Constant Fahrenheit/Celsius Lfpttr/Lcpttr (26); Function Revision History; Identification; Application - Hitachi Relion 670 Series Applications Manual

Section 8
Current protection
8.5 Thermal overload protection, one time constant
Fahrenheit/Celsius LFPTTR/LCPTTR (26)
8.5.1

Function revision history

Document
revision
A
B
C
D
E
F
G
H
J
K
M
8.5.2

Identification

Function description
Thermal overload protection, one time
constant, Fahrenheit
Thermal overload protection, one time
constant, Celsius
8.5.3

Application

Lines and cables in the power system are designed for a certain maximum load current level. If the
current exceeds this level the losses will be higher than expected. As a consequence the temperature of
the conductors will increase. If the temperature of the lines and cables reaches too high values the
equipment might be damaged:
• The sag of overhead lines can reach unacceptable value.
• If the temperature of conductors, for example aluminium conductors, gets too high the material will
be destroyed.
• In cables the insulation can be damaged as a consequence of the overtemperature. As a
consequence of this phase to phase or phase to ground faults can occur.
140
Product History
revision
2.2.1 -
2.2.1 -
2.2.2 -
2.2.3 -
2.2.3 -
2.2.3 -
2.2.4 -
2.2.4 -
2.2.4 -
2.2.5 -
2.2.6 LCPTTR - Default value of the setting Iref changed to 120% of IBase
LFPTTR - Default value of the setting Iref changed to 120% of IBase
IEC 61850
identification
LFPTTR
LCPTTR
© 2017 - 2023 Hitachi Energy. All rights reserved
IEC 60617 ANSI/IEEE C37.2
identification device number
26
26
Phasor measurement unit RES670
1MRK511407-UUS Rev. N
IP14512-1 v8
GUID-D0DBCC3B-E613-4C45-99FF-6D2824712DF1 v1
M17106-1 v7
M15283-3 v9
Application manual