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Electric Vehicle Charging


Transformers are increasingly being 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 Sentinel K-Rated distribution transformers should be considered to effectively operate with these harmonics while the HPS Sentinel H harmonic mitigating 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 HPS Sentinel distribution transformers or by medium voltage dry-type HPS Millennium and HPS EnduraCoil transformer lines. 

Three phase autotransformers and single phase HPS PowerPlus Mini Power Centers also offer critical space and installation time savings in many applications. 

   Level 1  Level 2  Level 3
 Typical Load Per Unit  1 to 2 kVA  3 to 8 kVA  200 to 500 kVA
 Typical Feed Voltage  120 to 240  240 to 480. Fleet and parking lots may
be fed from medium voltage
 480 or medium voltage
 Phase  Usually Single  Single or three depending on
number of installation