Three-Phase Thermal Protection For Feeders, Cables And Distribution Transformers T1Pttr - ABB RELION REC615 Technical Manual

Protection functions
Table 286: (F)DPHLPDOC Technical revision history
Technical revision
B
C
D
E
4.1.3 Three-phase thermal protection for feeders, cables and
distribution transformers T1PTTR
4.1.3.1 Identification
Function description
Three-phase thermal protection for
feeders, cables and distribution
transformers
4.1.3.2 Function block
Figure 134: Function block
4.1.3.3 Functionality
The increased utilization of power systems closer to the thermal limits has
generated a need for a thermal overload function for power lines as well.
A thermal overload is in some cases not detected by other protection functions,
and the introduction of the three-phase thermal protection for feeders, cables and
distribution transformers function T1PTTR allows the protected circuit to operate
closer to the thermal limits.
An alarm level gives an early warning to allow operators to take action before the
line trips. The early warning is based on the three-phase current measuring function
using a thermal model with first order thermal loss with the settable time constant.
If the temperature rise continues the function operates based on the thermal model
of the line.
266
Change
Added a new input
Step value changed from 0.05 to 0.01 for the
Time multiplier setting.
Monitored data VMEM_USED indicating volt-
age memory use.
Internal improvement.
IEC 61850 IEC 60617
identification identification
T1PTTR 3Ith>F
1MRS758755 C
NON_DIR
ANSI/IEEE C37.2
device number
49F
REC615 & RER615
Technical Manual