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1MRK 502 071-UUS A
Generator protection REG670 2.2 ANSI and Injection equipment REX060, REX061, REX062
Application manual
ExpectedLife: The transformer expected insulation life in hours can be set by this
setting. As per IEEE C57.91-1995 the normal life expectancy at a continuous hot spot
temperature of 110 ̊ C is 180,000 Hours.
AgeingRateMeth: This setting is used to select the method to be used for transformer
insulation relative ageing rate calculation between IEC standard method and IEEE
standard method. It has the following options:
•
IEC: Transformer insulation age calculation based on IEC standard method.
•
IEEE: Transformer insulation age calculation based on IEEE standard method.
ThermalUpgrade: This setting is used to select the transformer insulation paper type
between thermally upgraded insulation and normal insulation. It has the following
options:
•
Upgraded: The function considers the given transformer has thermally upgraded
paper insulation.
•
Normal: The function considers the given transformer has normal insulation.
TimeToUpdate: This setting is used to set the time interval for updating the transformer
insulation loss of life calculation outputs LOLINDAY and LOLINYRS. It can be
selected as 1 hour/ 2 hour/ 4 hour/ 8 hour/ 12 hour/ 24 hour depending on user
requirement.
Two settable warning levels are available for hot spot temperature with separate
outputs. If warning level exceeds for the set time, an alarm is generated.
IEEE C57.96-1995 has suggested maximum temperature limits for the four types of
loading, see table 71.
Table 71:
Suggested maximum temperature limits
Type of temperature Normal life
expectancy loading
Insulated winding
120
hot spot
temperature in °C
Top oil
105
temperature in °C
IEEE standard has also suggested the limits of temperature and load for loads higher
than transformer nameplate.
•
For distribution transformers with 65°C hot spot temperature rise:
Planned loading
Long term loading
beyond nameplate
rating
130
140
110
110
Section 17
Monitoring
GUID-B170CF21-839E-4246-A607-55A8999FAD07 v1
Short term loading
180
110
723
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