ABB TCC300, Руководство пользователя, Страница: 596 / 716

high side is not connected together then may need to adjust the tap positions to get
zero DVAR current or the minimum value possible.
23. Manually Lower Transformer 3, one or two taps.
24. Manually Raise Transformers 1 and 2, one or two taps.
The regulated voltage should still be in band near the center of the band width.
25. Verify the following:
• The DVAR current on Transformer 3 is Leading
• The DVAR current on Transformers 1 and 2 is Lagging
• The DVAR current on Transformer 3 will have twice the magnitude of
Transformers 1 and 2
• The DVAR current on Transformers 1 and 2 should have the same magnitude
If the load is not evenly distributed between the transformers, then the voltage on the
transformer with the larger load may decrease and the control may call for a raise.
The voltage on the transformer with the smaller load may increase and its control
may call for a lower.
26. Open the Tie Breaker between Transformer 2 and Transformer 3 with Transformer
1 still connected to Transformer 2.
27. Verify that the controls are not calling for any tap change operations.
The load current does not ha ve to be the same when the Tie Breaker opens and the
voltage may change based on the loading of the transformers.
28. Verify that Transformer 3 DVAR current is at or near zero.
29. If necessary, manually initiate tap change operations to bring the voltage back into
band.
30. Verify that Transformer 1 and 2 DVAR current is at or near zero (because they are
on the same tap position).
31. Raise Transformer 2, one tap and verify the following:
• DVAR current on Transformer 2 is lagging
• Transformers 1 DVAR current is leading
• The magnitude of the DVAR Current on Transformer 1 and 2 should be the
same
• Transformer 3 DVAR current should be at or near zero
32. Manually place the transformers to the same tap position (or the same difference as
noted above).
33. Close the Tie Breaker between Transformer 2 and Transformer 3.
34. Verify that the DVAR current in all the transformers is at or near zero.
Assuming all the transformers are the same and the high side sources are all
connected together, only one high side source for the paralleled transformers. If the
high side is not connected together then it may be necessary to adjust the tap
positions to achieve zero DVAR current or the minimum value possible.
35. Manually Lower Transformer 1, one or two taps.
36. Manually Raise Transformers 2 and 3, one or two taps.
The regulated voltage should still be in band near the center of the band width.
37. Verify the following:
Section 9
1VAC388793-MB A
Testing
590 TCC300
User Manual