ABB Relion 670 Series Applications Manual page 515

1MRK 511 401-UEN Rev. K
IEEE C57.96-1995 has suggested maximum temperature limits for the four types of loading,
see table 74.
Table 74:
Type of temperature Normal life
Insulated winding
hot spot
temperature in °C
Top oil
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:
•
•
•
• For power transformer with 65°C hot spot temperature rise:
•
•
•
Settings related to warning and alarm are:
WrnHPTmpLev1 : This setting is used to set the level 1 value for hot spot temperature warning.
WrnHPTmpLev2 : This setting is used to set the level 2 value for hot spot temperature warning.
This should be more than the
tDelayToAlarm1 : This setting is used to set the time delay for the level 1 hot spot temperature
alarm. This time setting can be less than the winding time constant. For example if the
winding time constant is 420 sec, this setting can be 400 sec.
tDelayToAlarm2 : This setting is used to set the time delay for the level 2 hot spot temperature
alarm. This should be less than time setting in
18.11.3 Setting example
18.11.3.1 Transformer Rated Data
Table 75:
Parameter
Frequency
Rated Power
Voltage ratio
Tap changer
Winding 1 rated current
Winding 2 rated current
Winding 3 rated current
Table continues on next page
Bay control REC670
Application manual
Suggested maximum temperature limits
expectancy loading
120
105
Top oil temperature = 120°C
Hot spot winding temperature = 200°C
Short-time loading (1/2 h or less) = 300%
Top oil temperature = 110°C
Hot spot winding temperature = 180°C
Maximum loading = 200%
WrnHPTmpLev1 setting.
Transformer Rated Data
Value
© Copyright 2017 Hitachi Power Grids. All rights reserved
Planned loading
beyond nameplate
rating
130
110
tDelayToAlarm1 .
50 Hz
500 MVA / 500 MVA / 20 MVA
415 kV / 230 kV / 20 kV
±9
696 A
1255 A
577 A
Long term loading Short term loading
140 180
110 110
GUID-B3AE440F-CC5E-4742-9483-8D6448A476C8 v1
Note
1.67% of 230 kV
Section 18
Monitoring
509