Function Block; Functionality; Operation Principle - ABB RELION 611 Series Technical Manual
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Also See for RELION 611 Series:
- Engineering manual (108 pages) ,
- Applications manual (76 pages) ,
- Installation manual (68 pages)
Table of Contents
1MRS757454 D
4.1.3.2
4.1.3.3
4.1.3.4
611 series
Technical Manual
Function block
A070691 V3 EN
Figure 59:
Function block
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.
Re-energizing of the line after the thermal overload operation can be inhibited during
the time the cooling of the line is in progress. The cooling of the line is estimated by
the thermal model.
Operation principle
The function can be enabled and disabled with the Operation setting. The
corresponding parameter values are "On" and "Off".
The operation of T1PTTR can be described using a module diagram. All the modules
in the diagram are explained in the next sections.
The function uses ambient temperature which can be measured locally or remotely.
Local measurement is done by the protection relay. Remote measurement uses analog
GOOSE to connect AMB_TEMP input.
If the quality of remotely measured temperature is invalid or
communication channel fails the function uses ambient temperature
set in Env temperature Set.
Section 4
Protection functions
131
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