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base.dss file needs .1.2.3.4 and conn=delta phases for wye-delta xfmrs #17

Closed AAndersn closed 3 years ago

AAndersn commented 3 years ago

OpenDSS has a severe phase imbalance on the high-side of wye-delta step-up transformers for DER when the phases are not specified as .1.2.3.4. Also, DER connection needs to be specified as delta.

Original DSS file:

New Generator.MicroTurb-4 bus1=m1069-MT1 kV=0.480 kW=200 kVA=250 pf=0.9 Xdp=0.27 Xdpp=0.2 H=2 conn=delta mode=1 !Operating in constant pf mode per CA Rule 21
New Transformer.1069-MT1 XHL=5.75  kVA=300 Conns=[wye, Delta]
~ wdg=1 bus=M1069215.1.2.3.4  kV=12.47
~ wdg=2 bus=M1069DER480-1     kV=0.480
Values for:  TRANSFORMER.1069-MT1
Bus1= m1069215.1.2.3.4
Bus2= m1069der480-1

Distance from Meter:  22.223 kM ( 13.803 mi)
Power Flow:           -99.842 kW + j  -46.167 kvar

Phase Currents:         5.032   5.032   5.033   0.000 Amps
Phase Voltages(L-N):    7.417   7.235   7.207   0.111 kV
Per Unit Voltages:      1.030   1.005   1.001   0.015

Losses for this Element:
TotalLosses:    0.158 kW + j   2.265 kvar

CIM XML file:

<cim:PowerTransformerEnd rdf:ID="_22451DED-DDE7-4A63-9AAE-3197B06E148B">
  <cim:IdentifiedObject.mRID>_22451DED-DDE7-4A63-9AAE-3197B06E148B</cim:IdentifiedObject.mRID>
  <cim:IdentifiedObject.name>1069-mt1_End_1</cim:IdentifiedObject.name>
  <cim:PowerTransformerEnd.PowerTransformer rdf:resource="#_B2350906-72C1-439C-AE25-A28A05F3C884"/>
  <cim:PowerTransformerEnd.ratedS>300000</cim:PowerTransformerEnd.ratedS>
  <cim:PowerTransformerEnd.ratedU>12470</cim:PowerTransformerEnd.ratedU>
  <cim:PowerTransformerEnd.r>1.0366727</cim:PowerTransformerEnd.r>
  <cim:PowerTransformerEnd.connectionKind rdf:resource="http://iec.ch/TC57/CIM100#WindingConnection.Y"/>
  <cim:PowerTransformerEnd.phaseAngleClock>0</cim:PowerTransformerEnd.phaseAngleClock>
  <cim:TransformerEnd.endNumber>1</cim:TransformerEnd.endNumber>
  <cim:TransformerEnd.grounded>false</cim:TransformerEnd.grounded>
  <cim:TransformerEnd.Terminal rdf:resource="#_2FED283E-B508-4434-A3D2-A65AC877DBB5"/>
  <cim:TransformerEnd.BaseVoltage rdf:resource="#_9D8652E0-A64E-4333-BE4D-9221C40E469E"/>
</cim:PowerTransformerEnd>
<cim:PowerTransformerEnd rdf:ID="_D8065C9A-E349-4EDA-83E7-29E849D492F8">
  <cim:IdentifiedObject.mRID>_D8065C9A-E349-4EDA-83E7-29E849D492F8</cim:IdentifiedObject.mRID>
  <cim:IdentifiedObject.name>1069-mt1_End_2</cim:IdentifiedObject.name>
  <cim:PowerTransformerEnd.PowerTransformer rdf:resource="#_B2350906-72C1-439C-AE25-A28A05F3C884"/>
  <cim:PowerTransformerEnd.ratedS>300000</cim:PowerTransformerEnd.ratedS>
  <cim:PowerTransformerEnd.ratedU>480</cim:PowerTransformerEnd.ratedU>
  <cim:PowerTransformerEnd.r>0.001536</cim:PowerTransformerEnd.r>
  <cim:PowerTransformerEnd.connectionKind rdf:resource="http://iec.ch/TC57/CIM100#WindingConnection.D"/>
  <cim:PowerTransformerEnd.phaseAngleClock>1</cim:PowerTransformerEnd.phaseAngleClock>
  <cim:TransformerEnd.endNumber>2</cim:TransformerEnd.endNumber>
  <cim:TransformerEnd.grounded>false</cim:TransformerEnd.grounded>
  <cim:TransformerEnd.Terminal rdf:resource="#_76439C28-EC83-46A3-B168-E7D43DE1606E"/>
  <cim:TransformerEnd.BaseVoltage rdf:resource="#_72660C43-FE55-4DFD-84BC-3B52724AAC2C"/>
</cim:PowerTransformerEnd>
<cim:PowerTransformer rdf:ID="_B2350906-72C1-439C-AE25-A28A05F3C884">
  <cim:IdentifiedObject.mRID>_B2350906-72C1-439C-AE25-A28A05F3C884</cim:IdentifiedObject.mRID>
  <cim:IdentifiedObject.name>1069-mt1</cim:IdentifiedObject.name>
  <cim:Equipment.EquipmentContainer rdf:resource="#_EE71F6C9-56F0-4167-A14E-7F4C71F10EAA"/>
  <cim:PowerTransformer.vectorGroup>Yd1</cim:PowerTransformer.vectorGroup>
  <cim:PowerSystemResource.Location rdf:resource="#_7E790F7D-719D-4ABB-A38D-FCFA1F803BD9"/>
</cim:PowerTransformer>

Exported base.dss file:

new Generator.microturb-4 phases=3 bus1=m1069-mt1.1.2.3 model=1 kv=0.48 kva=250.00 kw=100.00 kvar=48.43
new Transformer.1069-mt1 phases=3 windings=2 xhl=5.750000 %imag=0.000 %noloadloss=0.000
~ normamps=15.28 emergamps=20.83
~ wdg=1 bus=m1069215 conn=w kv=12.470 kva=300.0 %r=0.200000
~ wdg=2 bus=m1069der480-1 conn=d kv=0.480 kva=300.0 %r=0.200000
Values for:  TRANSFORMER.1069-MT1
Bus1= m1069215
Bus2= m1069der480-1

Distance from Meter:   0.000 kM (  0.000 mi)
Power Flow:          -100.048 kW + j  -45.360 kvar

Phase Currents:         2.949   5.203   8.295   9.165 Amps
Phase Voltages(L-N):    7.410   7.261   7.233   0.000 kV
Per Unit Voltages:      1.029   1.008   1.005   0.000

Losses for this Element:
TotalLosses:    0.217 kW + j   3.117 kvar

Modified base.dss file:

new Generator.microturb-4 phases=3 bus1=m1069-mt1.1.2.3 mode=1 kv=0.48 kva=250.00 kw=100.00 kvar=48.43 conn=delta
new Transformer.1069-mt1 phases=3 windings=2 xhl=5.750000 %imag=0.000 %noloadloss=0.000
~ normamps=15.28 emergamps=20.83
~ wdg=1 bus=m1069215.1.2.3.4 conn=w kv=12.470 kva=300.0 %r=0.200000
~ wdg=2 bus=m1069der480-1 conn=d kv=0.480 kva=300.0 %r=0.200000
Values for:  TRANSFORMER.1069-MT1
Bus1= m1069215.1.2.3.4
Bus2= m1069der480-1

Distance from Meter:   0.000 kM (  0.000 mi)
Power Flow:           -99.792 kW + j  -46.126 kvar

Phase Currents:         5.019   5.019   5.020   0.000 Amps
Phase Voltages(L-N):    7.428   7.254   7.220   0.109 kV
Per Unit Voltages:      1.032   1.008   1.003   0.015

Losses for this Element:
TotalLosses:    0.157 kW + j   2.253 kvar
temcdrm commented 3 years ago

There are actually two issues here:

1) The original wye ungrounded transformer was not carried through as ungrounded in the export, to fix in CIMHub. 2) The original interconnection transformer was ungrounded on both sides, as was the DER. This would not reflect a real system, e.g., violates NEC, and may reflect an issue elsewhere in the original model. To fix elsewhere, before this model is submitted for IEEE validation.

temcdrm commented 3 years ago

Fixed in https://github.com/GRIDAPPSD/CIMHub/commit/b965e3df77c50a1cbf3250dee128fcbf2d41c926 Test by python3 test_xfmr.py in ieee4 directory, feature/cimext branch