ABB Relion 670 Series Applications Manual page 478

Section 17
Monitoring
17.10.3 Setting guidelines
The settings
resolution of the settings is 0.1 hours (6 minutes).
The limit for the overflow supervision is fixed at 99999.9 hours.
The setting
17.11 Estimation of transformer insulation life LOLSPTR
(26/49HS)
Function description
Estimation of transformer winding
insulation life
17.11.1 Application
A typical power transformer is composed of:
• Laminated steel core with copper or aluminium windings
• Solid refined paper insulation
• Highly refined mineral oil as insulating and cooling medium for the entire transformer
The oil is cooled by a separate cooling system using air or water. The core, windings and insulation
have specific thermal capabilities.
Losses in the winding and core can cause temperature rises in the transformer, which is
transferred to the insulating oil. Failure to limit these temperature rises to the thermal capability
of the insulation and core materials can cause premature failure of the transformer.
A transformer is rated at the power output. It can continuously deliver at rated voltage and
frequency without exceeding the specified temperature limit. This temperature rise is based on
thermal limitations of the core, winding and insulation. Therefore, transformer MVA rating is
based on maximum allowable temperature of the insulation. Design standards express
temperature limits for transformers exceeds ambient temperature. Use of ambient temperature
as a base ensures that a transformer has adequate thermal capacity and independent of daily
environmental conditions.
Transformers in the power system are designed to withstand certain overload conditions. The
permissible transformer load level is highly depends on the transformer cooling system. Both IEEE
and IEC standards have established transformer thermal model for all cooling system types and
described formulae for transformer temperature calculation.
472
tAlarm and tWarning are user settable limits defined in hours. The achievable
tAlarm and tWarning are independent settings, that is, there is no check if tAlarm >
tWarning .
tAddToTime is a user settable time parameter in hours.
IEC 61850
identification
LOLSPTR
© Copyright 2017 ABB. All rights reserved
IEC 60617 ANSI/IEEE C37.2
identification device number
26/49HS
3Ihp>T
1MRK 511 401-UUS F
GUID-D3BED56A-BA80-486F-B2A8-E47F7AC63468 v1
GUID-D9D1F036-EC75-40A8-860F-192CF1F6F759 v1
GUID-A3D72F4B-9567-4DF0-867A-9F657A7E9291 v1
GUID-7F37B3D6-C98E-4780-AB5B-12780566FFA2 v1
Bay control REC670
Application manual