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D: Menu Parameters
D.1 <CONFIGURE> menu:
Leading and Lagging Regulators
The following steps will help you determine which of the
two regulators in a Delta configuration is "leading" and
which is "lagging" on an open Delta installation:
1.
Disable automatic control of tap changer as follows:
Set Raise/Lower tap switch to OFF. Set Remote/Auto/
Manual switch on both controllers to Manual.
2.
Use the Configuration Keys to temporarily set both
controllers to System type = WYE. This will be
corrected in step 7.
3.
Ensure that there is load current on the line. Load
current must be of sufficient magnitude to cause a
definite response of the line drop compensation
circuit. Normally, 25% of the regulator setting will be
adequate.
4.
Adjust both front panel controls to the same settings:
Bandwidth
Voltage Level
Time Delay
Resistance Volts
Reactance Volts
5.
Set the Remote/Auto/Manual switch to AUTO on both
controllers.
6.
Allow both regulators to run and come to rest in band.
The regulator whose tap position is closest to
maximum is the "lagging" regulator. The other
regulator is the "leading" regulator.
Note: The amount of tapchange excursion can be made
more or less, if desired, by appropriate adjustment of the
reactance volts setting.
7.
Use the Configuration keys to set the System type to
Delta Lead for the leading regulator and to Delta Lag
for the lagging regulator, as determined in step 6.
D.2 <REGULATOR> menu:
Line Drop Compensation
There are several methods used to determine line drop
compensation settings, The "Load Center" method is
probably the most commonly used and most clearly
illustrates the procedure.
1.
Using knowledge of the distribution feeder and the
tables below, establish the conductor resistance and
reactance per mile of feeder.
Siemens Industry, Inc.
Appendix D: Menu Parameters
2.0 V
120 V
0 Seconds
0 V
(+) 12
EXAMPLE: Conductor 4/0 ACSR, Regular Flat Spacing at
24 inches.
R=0.592 ohms/mile X=0.692 ohms/mile
2.
Determine compensation multiplier, k, as
Single phase
Wye Connected
Delta Connected
EXAMPLE: The regulators involved are 3 - 333 kVA at 7.2
kV configured in a wye-connected three phase bank. (The
CT primary for this regulator is 400 A.)
3.
Determine the Line Drop Compensation Settings
Resistive Compensation Setting = k x line length (mi) x
resistance (ohms/mi)
Reactive Compensation Setting = k x line length (mi) x
reactance (ohms/mi)
EXAMPLE: The line is 3 miles long.
Resistance Setting = 6.67 x 3 x 0.592 = 12V
Reactance Setting = 6.67 x 3 x 0.692 = 14V
61
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