ABB Relion 670 Series Applications Manual page 498

Section 17
Monitoring
and once the alarm is raised, then control actions can be taken such as changing auto-reclosing
settings.
MaxI2tW1 : It defines the I
shall be set based on the withstand capability of each winding with respect to corresponding
rated current. Similarly, the threshold limit for winding 2 and winding 3 shall be set using
MaxI2tW3 settings.
and
Even though transformer damages caused by through faults are cumulative by nature, individual
through fault events also require attention. This is because the impact of several small through
faults can be less compared to one heavy through fault.
The PTRSTHR (51TF) function monitors each through fault events and accumulates the calculated
2
I t values for each fault to determine the cumulative effect. This cumulative I
windings phase-wise and when this value exceeds the cumulative
MaxI2tCmlW1 : It defines the cumulative I
phase. Similarly, the cumulative threshold limit for winding 2 and winding 3 shall be set using
MaxI2tCmlW2 and MaxI2tCmlW3 settings.
The alarm signal due to individual event
the set minimum time delay, whichever is longer. The alarm signal due to cumulative
continuously until the cumulative
tPulse : It defines the pulse duration for an individual event I
Consider all the calculations based on through fault not as a precise indicator of transformer
health. These values indicate that the transformer should be inspected, they do not indicate a
strict necessity to shut-down the transformer.
17.12.3.6
Initial values for cumulative
The calculated cumulative
counts can be reset with preset values using command inputs under the clear menu or via binary
inputs. The following parameters which are set under advanced parameters are related to the
initial values of cumulative
InitCI2tW1L1 : It defines the initial cumulative I
cumulative
and C in the parameters name. For other windings, the initial cumulative
using the parameters which are designated with W2 and W3 in the parameters name.
InitTFCntW1L1 : It defines the initial fault counter value of winding 1 and phase A. Similarly, the
initial fault counter value for other phases B and C shall be set using parameters which are
designated with B and C in the parameters name. Also, for other windings the initial fault counter
value shall be set using the parameters which are designated with W2 and W3 in the parameters
name.
InitCmlTFCnt : It defines the initial overall fault counter value for the transformer.
492
2
t threshold limit for an individual event or fault per phase. This setting
2
I t values are reset to a lower value than the set limit.
2
I t values for each phase of windings and number of through faults
2
I t and number of through faults.
2
I t value for B and C phase shall be set using parameters which are designated with B
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2
t threshold limit for all fault events in winding 1, per
2
I t will be reset either after the ongoing fault is cleared or
2
2
I t and number of through faults
2
t value for winding 1 and phase A. Similarly, initial
2
t is calculated for all
2
I t set limit, an alarm is raised.
t alarm.
GUID-AA90D6D8-4AF2-4D5D-BCD9-308CD7578D05 v1
2
I t values shall be set
Bay control REC670
Application manual
1MRK 511 401-UUS F
MaxI2tW2
2
I t is set high