How do we select the proper voltage transformer for a given application?
In order to select the proper indoor type voltage t transformer for an application, there are four phases need to be addressed:
1- Define customer requirements based on the primary circuit and the metering and protection chains; i.e. define customer requirements in terms of voltage transformer specifications, key specifications can be summarized as follows:
Rated primary voltage(s) or insulation level Ur/Ud/Ui in kV.
Rated secondary voltage(s).
Rated frequency (e.g. 50 or 60Hz).
Earthing system (isolated or not).
Desired accuracy class in measurement chain (e.g. class 1, 0.5 …etc).
Desired rated burden (in VA) for measurement chain (e.g. 25VA).
Desired accuracy class in protection chain (e.g. class 3P, 6P …etc).
Desired rated burden (in VA) for protection chain (e.g. 25VA).
Special requirements such as out-of-standard temperature/environment/altitude; connections; terminal covers; etc
Installation type: either inside a SE cubicle (in this case the cubicle type and rated current need to be known) or in a non-SE cubicle.
2- Select a “referenced” product from the CT/VT catalog (please refer to the latest catalog published). Note that our standard VT references are for only for non-isolated neutral systems unless indicated differently.
3- If no suitable VT has been found, you can still check the feasibility of the solution on “ELONET” using the “configured order” option for a given VT type or SE cubicle (note: in case a feasible solution has been found, the configured VT can then be ordered/procured via dedicated supply chain or intra-group purchase team).
4- If still no solution found, you need to fill-in a consultation form (per VT solution required) and send it back to technical support team for feasibility study; consultation form attached.