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6.2.11.5 Demand history
Demand History quantities are the maximum and minimum values for the period since the
last reset command. These are retained in non-volatile memory. A real-time clock allows
the recording of a date/time stamp with each Demand History quantity. The following are
available for drag hand use:
• Min/Max tap position (when Tap Position is enabled)
• Min Load voltage (120 V base)
• Max Load voltage (120 V base)
• Max Primary current
• Max Primary watts, kW or MW
• Max Primary VAr, kVAr or MVAr
• Max Primary VA, kVA or MVA
• Power Factor at max VA
Where primary quantities are used, values displayed are single-phase or three-phase as
defined in the Primary Power Display Screen of the Configuration Menu.
When the TCC300 Tapchanger Control is used with an ABB adapter
panel, the panel’s drag hands reset button only resets the mechanical drag
hands of the regulator or LTC transformer. The button does not reset the
tap drag hands information stored in the control. The maximum and
minimum tap position of the control should always be reset when the
mechanical drag hands are reset.
The values retained in memory are time-tagged quantities that are calculated using the
demand period selected (5, 10, 15, 30 or 60 minutes). For voltage, values are the average
of samples taken over a period of 32 seconds which avoids undue retention of momentary
voltage transients. The load power factor retained is the value at the time of max VA.
When selected, two screens for each parameter cycle continuously and indicate the value,
date and time of each parameter. The E indicates that the drag hand can be reset by pushing
ENT.
The control is equipped with a real-time, 24
‑
hour clock which is used with the drag hand
feature to record date/time stamp information on quantities saved in memory. The power
source for the clock is maintained for at least 24 hours during a system power outage by
a charged capacitor (no battery). If the power outage lasts longer than 24 hours, check the
clock and reset if necessary.
Section 6
1VAC388793-MB A
Configuration
376 TCC300
User Manual