5 Reading and Interpreting MJ-XL Control Panel Data
Siemens Power Transmission & Distribution, Inc. 37
5.7 Operation Counter Data -
the <COUNTERS> Menu
Operation counters record the stepping operations of the
regulator tap changer (see Table 5.7).
To retrieve Tap Changer data, use the Menu Selection
keys to access the< COUNTERS> Menu; then use the Ù
and Ú keys to sequence through the data.
Dead Reckoning for Siemens Regulators
The control program keeps track of the regulator tap posi-
tion by means of a “dead reckoning” procedure, analo-
gous to navigational dead reckoning. Dead reckoning must
start from a known position. MJ-X
L
dead-reckoning begins
at Neutral (U12 active) or when an operator inputs a tap
position value. Subsequently, when the microprocessor
requests a tap raise/lower (J/K), and the regulator makes
the tap change (asserting Operations Count signal U10),
the control program updates the tap position value. By this
procedure, the MJ-X
L
maintains continuous tap position
information.
Since you can change the MJ-X
L
tap position value, it is
unnecessary to return the tap to Neutral to synchronize
tap tracking.
If, for some reason, a tap change command is not con-
firmed within an appropriate period of time, an Alert con-
dition is raised and dead reckoning is discontinued until
the tap changer once again signals Neutral. Similarly, an
Alert condition is activated if an Operation count signal is
received when no tap change command was issued; or if
the U12 PDS lead signals that the tap changer has passed
through neutral at a time when the assumed dead-reckon-
ing position is not neutral.
Note: For application on other manufacturer’s regula-
tors and LTC apparatus, the MJ-X
L
implements
a similar dead reckoning procedure for tap
tracking. The details of the tap tracking
approach for these applications are included in
the respective Application Note.
Table 5.7 Counter Data Items
Total Ops The total number of tap changes
2
Reset Date of last Elapsed Ops counter reset
Reset Time of last Elapsed Ops counter reset
Elapsed Ops Total number of tap changes since last reset
1
24 HR Ops Number of tap changes in the past 24 hours
1
30 Day Ops Number of tap changes in the past 30 days
1
MTD Ops Number of tap changes this month
1
Last Month Number of tap changes last month
1
YTD Ops Number of tap changes this year
1
Last Year Number of tap changes last year1
Tap Present position of the tap changer
1
Tapmax Maximum tap position since last reset
1, 3, 4
Tapmin Minimum tap position since last reset
1, 3, 4
1. To reset, use Cancel/Reset key.
2. To change value, use the Change/Scroll/Save keys.
3. Tap position is determined by the “dead reckoning” method
(see below)
4. To view, use Max/Min key.
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