ABB Relion 670 Series Applications Manual page 395

1MRK 511 401-UUS F
lead to the output signal TCERRAL being set high and TR1ATCC (90) or TR8ATCC (90) function
being blocked. Effectively this is then also a supervision of a run-away tap situation.
Hunting detection
Hunting detection is provided in order to generate an alarm when the voltage control gives an
abnormal number of commands or abnormal sequence of commands within a pre-defined period
of time.
There are three hunting functions:
1. The Automatic voltage control for tap changer function, TR1ATCC (90) for single control and
TR8ATCC (90) for parallel control will activate the output signal DAYHUNT when the number
of tap changer operations exceed the number given by the setting
last 24 hours (sliding window). Active as well in manual as in automatic mode.
2. TR1ATCC (90) or TR8ATCC (90) function will activate the output signal HOURHUNT when the
number of tap changer operations exceed the number given by the setting
during the last hour (sliding window). Active as well in manual as in automatic mode.
3. TR1ATCC (90) or TR8ATCC (90) function will activate the output signal HUNTING when the
total number of contradictory tap changer operations (RAISE, LOWER, RAISE, LOWER, and so
on) exceeds the pre-set value given by the setting
window specified via the setting parameter
Hunting can be the result of a narrow deadband setting or some other abnormalities in the control
system.
Wearing of the tap changer contacts
Two counters, ContactLife and NoOfOperations are available within the Tap changer control and
supervision function, 6 binary inputs TCMYLTC or 32 binary inputs TCLYLTC (84). They can be used
as a guide for maintenance of the tap changer mechanism. The ContactLife counter represents
the remaining number of operations (decremental counter) at rated load.
ContactLife
EQUATION1873 V2 EN-US
where n is the number of operations and α is an adjustable setting parameter,
default value is set to 2. With this default setting an operation at rated load (current measured on
HV-side) decrements the ContactLife counter with 1.
The NoOfOperations counter simply counts the total number of operations (incremental counter).
Both counters are stored in a non-volatile memory as well as, the times and dates of their last
reset. These dates are stored automatically when the command to reset the counter is issued. It is
therefore necessary to check that the IED internal time is correct before these counters are reset.
The counter value can be reset on the local HMI under Main menu/Reset/Reset counters/
TransformerTapControl(YLTC,84)/TCMYLTC:1 or TCLYLTC:1/Reset Counter and
ResetCLCounter
Both counters and their last reset dates are shown on the local HMI as service values under Main
menu/Test/Function status/Control/TransformerTapControl(YLTC,84)/TCMYLTC:x/
TCLYLTC:x/CLCNT_VALandMain menu/Test/Function status/Control/TransformerTapControl
(YLTC,84)/TCMYLTC:x/TCLYLTC:x/CNT_VAL
Bay control REC670
Application manual
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rated
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NoOpWindow within the time sliding
tWindowHunt . Only active in automatic mode.
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Section 14
Control
SEMOD159053-361 v4
DayHuntDetect during the
HourHuntDetect
SEMOD159053-376 v4
(Equation 128)
CLFactor , with
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