Abstract This paper presents a novel carbon metering method for distribution grids that fully considers the impact of harmonics on the grid. Harmonics are sinusoidal waves with frequencies that are integer multiples of the fundamental frequency, and the presence of harmonics can lead to power losses, damage to equipment and degradation of power quality, thus increasing carbon emissions from the grid. Currently available carbon measurement methods often do not take this into account, so a more accurate method is needed to assess the carbon emissions of distribution grids. This new method, based on the carbon flow theory of trending power distribution, combines harmonic energy correction and node carbon potential correction, and is able to accurately calculate the carbon emissions as well as the harmonic carbon correction for each node and branch in the distribution network. In order to evaluate the carbon behavior characteristics of users more comprehensively, the study also adopts the DTW-K-Means clustering technique to group distribution network users. This innovative approach provides an effective technical means and theoretical basis for the monitoring, assessment and management of distribution network carbon emissions. This innovative method provides effective technical means and theoretical basis for distribution network carbon emission monitoring, assessment and management, not only considering the impact of harmonics on power metering, but also more accurately portraying the carbon behavior of users, which is expected to provide strong support for the reduction of grid carbon emissions.