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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 cor-
rected in step 7 .
3.
Ensure that there is load current on the line. Load cur-
rent must be of sufficient magnitude to cause a defi-
nite response of the line drop compensation circuit.
Normally, 25% of the regulator setting will be ade-
quate.
4.
Adjust both front panel controls to the same settings:
Bandwidth
2.0 V
Voltage Level
120 V
Time Delay
0 Seconds
Resistance Volts
0 V
Reactance Volts
(+) 12
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 maxi-
mum 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 illus-
trates the procedure.
1.
Using knowledge of the distribution feeder and the
tables below, establish the conductor resistance and
reactance per mile of feeder.
EXAMPLE: Conductor 4/0 ACSR, Regular Flat Spacing at
24 inches.
Siemens Energy, Inc.
Appendix D: Menu Parameters
3
D
=
24 x 24 x 48
R=0.592 ohms/mile
2.
Determine compensation multiplier, k, as
•
Single phase
Current Transformer Rating
k = 2.0x
Voltage Transformer Ratio
•
Wye Connected
Current Transformer Rating
k = 1.0x
Voltage Transformer Ratio
•
Delta Connected
Current Transformer Rating
k = 1.73x
Voltage Transformer Ratio
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.)
k = 1.0
7200 / 120
Note: Multipliers for many common system voltages
and regulator ratings are included in tables D.4
and D.5 below.
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
=
30 inches
X=0.692 ohms/mile
400
= 6.67
63
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