ABB Relion REG670, Applications Manual

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Loss ratios at different tap positions are required for the calculation of top oil
temperature, especially when the transformer is using online tap changer. This loss
ratio is the ratio between load losses to no-load loss. It may vary from 6 -7 for
distribution transformer and 4-8 for power transformer. Normally it varies from 3 to
11. The function has the following settings related to loss ratio calculation.
RLRated : This setting is used to set the ratio of load losses to no-load loss at principal
tapping position.
RLHighRated : This setting is used to set the ratio of load losses to no-load loss at
principal t1 position.
RLMaxTap : This setting is used to set the ratio of load losses to no-load loss at
maximum tap position where maximum voltage is possible.
RLMinTap : This setting is used to set the ratio of load losses to no-load loss at
minimum tap position where minimum voltage is possible.
RatedVoltTap : This setting is used to set the position number of tap changer at rated
voltage.
HighVoltTap : This setting is used to set the position number of tap changer at possible
maximum voltage.
LowVoltTap : This setting is used to set the position number of tap changer at possible
minimum voltage.
The following settings are required to perform the calculation of top oil temperature
using monthly model of ambient temperature when AMBVALID is low:
JanAmbTmp : This setting is used to set the January month average ambient
temperature.
FebAmbTmp : This setting is used to set the February month average ambient
temperature.
MarchAmbTmp : This setting is used to set the March month average ambient
temperature.
AprilAmbTmp : This setting is used to set the April month average ambient
temperature.
MayAmbTmp : This setting is used to set the May month average ambient temperature.
JuneAmbTmp : This setting is used to set the June month average ambient temperature.
JulyAmbTmp : This setting is used to set the July month average ambient temperature.
AugAmbTmp : This setting is used to set the August month average ambient
temperature.
Section 17
1MRK 502 071-UEN -
Monitoring
662 Generator protection REG670 2.2 IEC and Injection equipment REX060, REX061, REX062
Application manual