Potential transformers or voltage transformers are designed for electrical power systems in order to step down the voltage to a safe level, which can then be fed to meters and relay components with lower voltage ratings. Commercial relays and meters used for protection and readings are produced for low voltage and therefore require a voltage transformer.
Three-phase units are commonly rated up to 36kV but for higher voltages, single phase units are usually installed. Voltage transformers for medium voltage circuits are produced with dry type insulation, for high and extra high voltage systems, oil immersed units are used. Resin encapsulated designs are used for systems up to 33kV.
The construction of a voltage transformer takes into account the following factors:
a. Output – seldom more than 200-300VA. Cooling is rarely an issue for these units.
b. Insulation – designed for the system impulse voltage level. Insulation volume is often larger than the winding volume.
c. Mechanical design – not usually necessary to withstand short-circuit currents.
Protection of Voltage Transformers
Voltage transformers can be protected by H.R.C. fuses on the primary side for voltages up to 66kV. Fuses do not usually have a sufficient interrupting capacity for use with higher voltages.
The secondary component of the voltage transformer should always be protected by fuses or miniature circuit breaker (MCB). The device should be located in close proximity to the transformer. A short circuit on the secondary circuit will produce a current significantly higher than the rated output and will result in overheating.Technical Parameter of JSZV-10R Voltage Transformers for your reference, if you need other types, feel free to contact us.
Technical data of the voltage transformer for measuring:
1. Technical data form
2. The conditions of the partial discharge test according to GB1207-2006《voltage transformer will be fulfilled without exception
3. The fusible cutout's type: XRNP□-12, 0.2A, 50kva
|Type||Rated voltage Tation(V)||Ratedoutput(VA)||Limit output(VA)||Rated insulated level（KV）|
|Type||Rated voltage Tation(V)||Max.short-time output rating(VA)||Rated insulates level(KV)|