This section contains parameters of 2-winding transformers. With the exception of the line shunts, all the per-unit impedances and admittances are based on the transformer’s own MVA base and the tap kVs. The admittances of the line shunts are based on the system MVA base and the nominal kV of the bus terminals. The grounding impedances are in ohms and should be entered without any multiplication by 3. The first line in the section must say: [2W TRANSFORMER DATA]. This is followed by the data described below. A blank line ends the section.
1. Bus1 Name: Bus name at one end of the transformer, enclosed in quotation marks.
2. Bus1 Base kV: Nominal kV of Bus1.
3. Bus2 Name: Bus name at the other end of the transformer, enclosed in quotation marks.
4. Bus2 Base kV: Nominal kV of Bus2.
5. Circuit Identifier: A 2-character circuit identifier in quotation marks. Parallel transformers must have different circuit identifiers.
6. In-Service Flag: 1 if the transformer is in-service; 0 if it is not. The default value is 1.
7. Meter Flag: 0.0 if the transformer is metered at Bus1, and 100.0 if at Bus2. No other values are allowed.
8. Branch Name: A 12-character name for the transformer, enclosed in quotation marks. The branch name is blank by default.
9. Bus1 Tap kV: The Bus1 winding tap voltage in kV, line-to-line. The default is the nominal kV of Bus1.
10. Bus2 Tap kV: The Bus2 winding tap voltage in kV, line-to-line. The default is the nominal kV of Bus2.
11. Auto-Transformer Flag: 1 if the transformer is an auto-transformer; 0 if it is not. An auto-transformer is assumed to be wye-connected.
12. R: Real part of the positive-sequence short-circuit impedance measured at the Bus1 terminal with the Bus2 terminal short circuited. The same value is used in the negative-sequence model. R and X are in per-unit based on transformer’s own MVA base and the tap voltages.
13. X: Imaginary part of the positive-sequence short-circuit impedance measured at the Bus1 terminal with the Bus2 terminal short circuited. The same value is used in the negative-sequence model. R and X cannot both be zero.
14. B: Positive-sequence susceptance (in per-unit on transformer’s own MVA base and tap voltages). The same value is used in the negative-sequence model. B must be zero or negative.
15. R0: Same meaning as R, except R0 is for the zero sequence.
16. X0: Same meaning as X, except X0 is for the zero sequence.
17. B0: Same meaning as B, except B0 is for the zero sequence.
18. Bus1 Winding Configuration: ‘G’ if wye connected, ‘D’ if delta connected, and ‘Z’ for a zigzag winding. The default is ‘G’. The table below lists winding configuration codes for the different transformer types supported by the program:
1. Wye-Wye: Winding configuration=’GG’; test configuration=’GG’, Auto flag=0.
2. Auto-Wye: Winding configuration=’GG’; test configuration=’GG’, Auto flag=1.
3. Wye-Delta, delta lags: Winding configuration=’GD’; test configuration=’GD’, Auto flag=0.
4. Wye-Delta, delta leads: Winding configuration=’GE’; test configuration=’GD’, Auto flag=0.
5. Delta-Delta: Winding configuration=’DD’; test configuration=’GG’, Auto flag=0.
6. Delta-Zigzag: Winding configuration=’ZD’; test configuration=’ZD’, Auto flag=0.
7. Wye-Zigzag, wye leads: Winding configuration=’ZG’; test configuration=’ZG’, Auto flag=0.
8. Wye-Zigzag, wye lags: Winding configuration=’ZX’; test configuration=’ZX’, Auto flag=0.
19. Bus2 Winding Configuration: ‘G’ or ‘X’ if wye connected, ‘D’ if delta connected and the delta is lagging the wye winding, or ‘E’ if delta connected and the delta is leading. See table in item 18.
20. Bus2 Winding Configuration in test: (Note: The Bus1 winding configuration in test is assumed to be ‘G’ always.) The Bus2 winding configuration in test is G if wye connected; D if delta connected and the delta was closed during the test. See table in item 18.
21. RG1: Grounding resistance in ohms. Meaningful only if the Bus1 winding configuration is G or Z. See Figure 4.6 for location of neutral impedances.
22. XG1: Grounding reactance in ohms. Meaningful only if the Bus1 winding configuration is G or Z.
23. RG2: Grounding resistance in ohms. Meaningful only for wye-wye transformers.
24. XG2: Grounding reactance in ohms. Meaningful only for wye-wye transformers.
25. RGN: Grounding resistance in ohms. Meaningful only for wye-wye transformers.
26. XGN: Grounding reactance in ohms. Meaningful only for wye-wye transformers.
27. Number of Ratings to follow: Must be 3.
28. MVA Rating 1: Three-phase MVA rating of transformer. Default value is 0.0.
29. MVA Rating 2: Three-phase MVA rating of transformer. Default value is 0.0.
30. MVA Rating 3: Three-phase MVA rating of transformer. Default value is 0.0.
31. LTC Side: 0 if the transformer does not have a movable tap or if the tap is locked. 1 if the movable tap is at the Bus1 side. 2 if the movable tap is at the Bus2 side.
32. LTC Type: 0 if the LTC regulates the voltage magnitude. 1 if the LTC regulates the MVAR flow. The MVAR regulation has not been implemented in the current version.
33. Minimum Tap: Minimum tap voltage in per-unit. The default is 0.51.
34. Maximum Tap: Maximum tap voltage in per-unit. The default is 1.50.
35. Step Size: The tap increment in per-unit. Specify 0.0 if the tap is continuous. The default is 0.00625.
36. Minimum Target: The minimum per-unit voltage or the minimum MVAR flow. The default is 0.51.
37. Maximum Target: The maximum per-unit voltage or the maximum MVAR flow. The default 1.50.
38. Regulated Bus Name: Name of the bus whose voltage magnitude is to be regulated by the LTC. The bus name is enclosed in quotation marks.
39. Regulated Bus Base kV: Nominal kV of the bus whose voltage magnitude is to be regulated by the LTC. Set the Regulated Bus Name to blank and the Regulated Bus Base kV to 0 if the LTC is locked or if it is regulating MVAR flow.
40. G1: Positive-sequence conductance of the line shunt on the Bus1 side. All line-shunt admittances are based on the system MVA base and the nominal kV of the branch terminals. The default value is 0.0.
41. B1: Positive-sequence susceptance in per unit of the line shunt on the Bus1 side. The default value is 0.0.
42. G2: Positive-sequence conductance in per unit of the line shunt on the Bus2 side. The default value is 0.0.
43. B2: Positive-sequence susceptance in per unit of the line shunt on the Bus2 side. The default value is 0.0.
44. G10: Zero-sequence conductance in per unit of the line shunt on the Bus1 side. The default value is 0.0.
45. B10: Zero-sequence susceptance in per unit of the line shunt on the Bus1 side. The default value is 0.0.
46. G20: Zero-sequence conductance in per unit of the line shunt on the Bus2 side. The default value is 0.0.
47. B20: Zero-sequence susceptance in per unit of the line shunt on the Bus2 side. The default value is 0.0.
48. Base MVA: With the exception of the line shunts, all the transformer impedances and admittances are based on this MVA base. The default is the system MVA base.
49. LTC center tap kV: Load tap changer center position in kV.
50. LTC Ganged Flag: 1 if this LTC moves in unison with other LTCs that control the same bus voltage. 0 otherwise.
51. LTC Adjustment Priority: 0 if ‘normal’, 1 if ‘medium’, and 2 if ‘high’.
52. Memo: Comments with a maximum of 512 characters. Any alpha-numeric characters can be used, except for the string delimiter (single or double quotation mark). The comment text is enclosed in quotation marks.
53. Tags: Tag string with a maximum of 512 characters. Tags in string are separated by semicolon. Any alpha-numeric characters can be used, except for the string delimiter (single or double quotation mark). The tag string is enclosed in quotation marks.
54 In-service Date: Set to 0 if not available. Otherwise enter an unsigned 32-bit integer that store the year/month/date information given by the CTime object in Microsoft Foundation Class.
55. Out-of-Service Date: Set to 0 if not available. Otherwise enter an unsigned 32-bit integer that store the year/month/date information given by the CTime object in Microsoft Foundation Class.
56. UDF: User-defined data fields. Enter the list of user defined field values as a tab delimited text string enclosed in single quotes.
An example 2-winding transformer data section is shown below.
[2W TRANSFORMER DATA]
'NEVADA' 132 'NEW HAMPSHR' 33 '1'= 1 0 'Nev/NH' 132 33 0 0 0.556 0 0 0.556 0 /
G G G 0 0 0 0 0 0 3 0 0 0 0 0 0.51 1.5 0.00625 0.51 1.5 '' 0 /
0 0 0 0 0 0 0 0 100 0 0 '' '' 0 0