ABB TCC300, Руководство пользователя, Страница: 547 / 716

The VAr Bias Pickup trigger timer will instantly reset to ZERO if the reactive power
measurement returns within the allowable band before VAr Bias becomes active.
Once VAr Bias is active, the control will remove the VAr Bias condition for the following
situations.
• When Max VAr Bias Duration is exceeded (see below description). – When reactive
power returns back in band within 90% of the VAr limits set by Lag or Lead % Bank
Size Pickup settings. For example, if the Upper VAr limit is 75 % of 12000 KVAr
bank then the level below which the control will return in band after going out above
the Upper VAr limit is 9*3000/10 = 2700 KVAr. Similarly if the Lower VAr limit is
at -3000 then the in band limit is -2700 KVAr.
The application of both the TCC300 Tapchanger Control and the Autodaptive Capacitor
Control(s) on a circuit provides for an interaction between the devices that provides for
faster response in times of rapidly changing conditions on the distribution system. For
example, if one regulator is serving 6 feeders, with each feeder using 1200 KVAr pole-top
feeder capacitor banks, and if each feeder is correctly compensating to within 400 KVAr,
all feeder bank controls would be considered to be operating correctly. However the
regulator would still be transforming up to 2400 KVAr (six feeders times 400 KVAr) from
the transmission system. The TCC300 Control on the regulator would detect this
condition and affect additional line capacitor operation by making a temporary voltage
level setting change. By effectively lowering its setting (delaying a voltage tap RAISE for
a short time), line capacitor bank control could be biased into operation sooner by the
tapchanger control. This would reduce losses of the circuit, provide a better voltage profile
and reduce the number of tapchanges.
In effect, when enabled user sets VAr Bias setting values at which bandcenter/bandwidth
is shifted to influence downstream Capacitor Control(s) into operation. Shifted
bandcenter/bandwidth returns to prior settings after measured VAr level returns within
band. If Max VAr bias Duration is exceeded, the shifted bandcenter/bandwidth returns to
prior setting and an ALARM is activated if configured to do so. The alarm will also have
corresponding communication events reported. When VAr Bias is active the OSC and
SOE may be triggered if selected.
7.8.1.1 Enabling Step VAr Bias Method from the HMI
1. Press the Up Arrow (SETP Hot Button) pushbutton to wake the unit. The menu will
advance to "SETPOINTS".
2. Press the Down Arrow pushbutton once. The unit will display the following:
Profile Settings
3. Press the Right or Left arrow pushbutton, as necessary, to navigate to the "VAr Bias"
menu.
1VAC388793-MB A
Section 7
Setpoints
TCC300 541
User Manual