The rapid charging of electric vehicles based on DC chargers will become the main form of electric vehicle charging

but its harmonic impact on the power grid cannot be ignored. The charging environment of electric vehicles is complex

and development of site test is conducive to accurately reflect its harmonic emission characteristics. To this end

the site test on 5 types of DC chargers at 4 fast charging sites is performed.First

the test object and test metho dare introduced. Then

based on the test result at site

the relationship between the harmonic emission level and the load rate

the harmonic spectrum characteristics of different types of chargers and the harmonic current cancellation effect are analyzed.After that

in view of the ultra high harmonic the emission characteristics of different types of the chargers are analyzed

and the phenomenon of secondary emission in the charging site is discovered. Throughout test at site

the harmonic emission characteristic of DC charger is fully mastered and the suggestions on the formulation of the assessment index and limits of the harmonics are proposed.