CKent
Electrical
- Aug 27, 2003
- 42
Good day!
For a 115kV/34.5k/13.8 kV 3-wdg power XFs, what should be the minimum insulation level of the 13.8 kV wdg if:
a. Unloaded tertiary, with no leads taken out
b. Tertiary shall be loaded, either via station service or capacitor for system improvement.
Note that tertiary is not corner grounded.
I am assuming that the 15 kV insulation level (110kV BIL) will suffice. However, some transformer manufacturers suggest to have 25kV insulation (which is about 150kV or 170kV BIL insulation). Of course this results to higher transformer costs.
Additionally, if we intend to ground one corner of the delta tertiary in cases we need to load it, what would be the voltage across the different phases?
For a 115kV/34.5k/13.8 kV 3-wdg power XFs, what should be the minimum insulation level of the 13.8 kV wdg if:
a. Unloaded tertiary, with no leads taken out
b. Tertiary shall be loaded, either via station service or capacitor for system improvement.
Note that tertiary is not corner grounded.
I am assuming that the 15 kV insulation level (110kV BIL) will suffice. However, some transformer manufacturers suggest to have 25kV insulation (which is about 150kV or 170kV BIL insulation). Of course this results to higher transformer costs.
Additionally, if we intend to ground one corner of the delta tertiary in cases we need to load it, what would be the voltage across the different phases?