This FAQ has been written for NEAL (North East Africa and Levant) region. If you are looking for information for another region, please select the correct country from the top-left dropdown in the page and 'Navigate to Browse FAQs' in the Support menu.
In order to select the proper indoor type voltage transformer for an application we need to 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