Transformer DY11 phasing LV to HV
Transformer DY11 phasing LV to HV
(OP)
Can anyone suggest a reliable way or anyway of ringing through a 6.6kV to 430v DY11 1000kVA Tx.
I want to identify the HV phase colours eg. which phase on the HV cable goes to A,B or C on the HV side of the Tx but don't want to have to melt down the HV box and cannot lift the Tx lid because of contaminated oil.
Does anyone know a device or method of connecting something to the HV cable and then from testing the LV side finding out what i want to know.
I want to identify the HV phase colours eg. which phase on the HV cable goes to A,B or C on the HV side of the Tx but don't want to have to melt down the HV box and cannot lift the Tx lid because of contaminated oil.
Does anyone know a device or method of connecting something to the HV cable and then from testing the LV side finding out what i want to know.






RE: Transformer DY11 phasing LV to HV
RE: Transformer DY11 phasing LV to HV
If there is no interconnection available why do you need to know? is rotation not sufficient.
RE: Transformer DY11 phasing LV to HV
There is a LV connection that i need this Tx to parallel with so you see i need to be sure that core 1 on the HV cable goes to A and the TX, core 2 on the HV cable goes to B and that Core 3 goes to C on the Tx this is what i would expect.
There would be a phasing method i could use after with the LV interconection but it would be nice if there was a method of finding out so i knew before that i was going to be right
RE: Transformer DY11 phasing LV to HV
RE: Transformer DY11 phasing LV to HV
I can understand you wanting to know the phasing before you do the jointing, hence it might not be practicable to do as isquaredr suggests. You could join one of the HV phases to one of the LV phases and inject 430V 3 phase on the PRIMARY 6.6KV WINDING. Measure the voltages developed between the secondary 430V terminals and the primary terminals and draw a vector diagram. Don't attempt any testing like this unless you are fully conversant with what you are doing and have taken the necessary safety precautions to avoid danger.
Regards
Marmite
RE: Transformer DY11 phasing LV to HV
The oil has PCBs in it (carsonagenic!)
Could you explain further ? Could a DC injection set be used do you think
RE: Transformer DY11 phasing LV to HV
Bill
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"Why not the best?"
Jimmy Carter
RE: Transformer DY11 phasing LV to HV
RE: Transformer DY11 phasing LV to HV
What we do at work is apply 1kVac on to the primary and measure the voltage on the secondary.
On a Dyn11 trx you find that applying 1kV between AB phases (HV side) you will get 37.61V only between "a" phase and neutral (LV side) and lower voltages between neutral and b &/or c.
If the same voltage is applied between BC phases, the same value (37.61V) is going to be found only between "b" phase and neutral (LV side).
Also applying the same voltage between CA phases (HV side) you will find 37.61V only between "c" phase and neutral (LV side).
Any other voltage that you find between the phases when doing the test will prove which phase is which...
Try using this excel sheet (in case you want to apply a different voltage for the test and let us know if that helps.
Good luck.
Dan de Freitas
Field Services