Modelling Two off Single Phase Auto Transformers Connected in Open Delta

[EddyWirbelstrom]

Two off Single Phase Auto Transformers Connected in Open Delta to Supply 3 Phase Load​

Single Phase Auto Transformer Data
From Fig 4 of attached file.
Cooper Power Systems Single Phase Step Voltage Regulator
kVA 220 / 246kVA
Load Amps 200 / 224 A
Rated Volts: 11000 V
Load Volts 5500V to 11600V ( not clear in photo )
Nameplate data Fig 4 does not include percentage impedance.

Question 1
How can two autotransformers connected in open delta as shown in Fig. 1 of attached file be modelled in PTW ( or other power systems software ) for 3 phase load flow and short-circuit calculations ?

 

[waross]

First:
CooperPower Systems Single Phase Step Voltage Regulator

The diagram shows a voltage drop or auto-transformer buck circuit, not a voltage regulator.

The primary winding will be connected line to line. For example "A" phase to "B" phase.
"A" Phase will continue to the load.

The secondary winding will be connected to "B" phase.
BUT: For a voltage regulator, it may have a center tap connected to "B" phase.
The secondary winding will have multiple taps. A movable contact will be connected to a tap and will feed the load.
As the supply voltage varies, the control circuitry will move the movable contact from tap to tap to provide the desired output or load voltage.
The center point of the secondary winding may be connected to "B" phase so that the regulator is able to either raise or lower the voltage depending on the supply voltage.
If a second similar transformer is connected between "A" and "C" phases, you have a three phase open delta voltage regulator.
"A" phase is common to both transformers and to the load.