Three Winding Transformer

Model of a three winding transformer. It is assumed, that node A is the node with highest, node B with intermediate and node C with lowest voltage.

The assumed mathematical model is inspired by ABB Schaltanlagenhanbuch [Gremmel1999], but with the addition of a central phase-to-ground admittance, cf. following picture.

Equivalent circuit diagram of a three winding transformer

“Star like” T-equivalent circuit diagram of a three winding transformer

Attributes, Units and Remarks

Type Model

All impedances and admittances are given with respect to the higher voltage side.

Attribute

Unit

Remarks

uuid

id

Human readable identifier

rScA

Ω

Short circuit resistance in branch A

rScB

Ω

Short circuit resistance in branch B

rScC

Ω

Short circuit resistance in branch C

xScA

Ω

Short circuit reactance in branch A

xScB

Ω

Short circuit reactance in branch B

xScC

Ω

Short circuit reactance in branch C

gM

nS

No load conductance

bM

nS

No load susceptance

sRatedA

kVA

Rated apparent power of branch A

sRatedB

kVA

Rated apparent power of branch B

sRatedC

kVA

Rated apparent power of branch C

vRatedA

kV

Rated voltage at higher node A

vRatedB

kV

Rated voltage at higher node B

vRatedC

kV

Rated voltage at higher node C

dV

%

Voltage magnitude increase per tap position

dPhi

°

Voltage angle increase per tap position

tapNeutr

Neutral tap position

tapMin

Minimum tap position

tapMax

Maximum tap position

Entity Model

Attribute

Unit

Remarks

uuid

–

id

–

Human readable identifier

operator

–

operationTime

–

Timely restriction of operation

nodeA

–

Higher voltage node

nodeB

–

Intermediate voltage node

nodeC

–

Lowest voltage node

parallelDevices

–
overall amount of parallel transformers to automatically
construct (e.g. parallelDevices = 2 will build a
total of two transformers using the specified parameters)

type

–

tapPos

–

Current position of the tap changer

autoTap

–

true, if there is a tap regulation apparent and active

Caveats

Nothing - at least not known. If you found something, please contact us!

Gremmel1999

Gremmel, H., Ed., Schaltanlagen. Cornelsen Verlag, 1999, Vol. 10, isbn: 3-464-48235-9.