Electric Vehicle Charging

electric vehicleTransformers are used to power electric vehicle charging stations. Several considerations need to be made when integrating transformers and electric vehicle chargers. Electric vehicle chargers act as non-linear loads to the power grid which causes current and voltage harmonics and distortion.  These harmonics make the proper selection of a transformer critical to the operation of both the transformer and the overall system.

Lower capacity Level 1 and Level 2 chargers are single phase loads that are most common in homes, parking lots and commercial fleets and typically have loads of 2 to 4 kVA. Installations with multiple units can cause critical harmonic current and voltage distortion. HPS EV charging distribution transformers with a k-rating should be considered to effectively operate with these harmonics while the harmonic mitigating of the EV charging transformer with zig-zag secondary winding can significantly improve power quality and reduce neutral currents through harmonic cancellation.

Level 3 chargers are commonly above 200 kVA to effectively charge a car in 10-20 minutes.  These large power draws often need to be supplied by large 600 volt class EV distribution transformers or by medium voltage dry-type transformers

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