In order to analyse the effect of harmonics on three-core cables

the electromagnetic-thermal coupling method is used to establish a finite element model

and the temperature rise characteristics of cables under the effect of harmo nics are analyzed through simulation.First

the cable loss changes due to harmonics are quantified.Then the electro magnetic-thermal coupling temperature calculation model is constructed

and the model accuracy is improved by correcting the parameters.Finally

the temperature field simulation under different harmonic conditions is carried out.The results show that: when the number of harmonics exceeds 19

the change rate of AC/DC resistance ratio with cross-sectional area decreases

and the loss of armor layer is positively correlated with the number of harmonics; the temperature of the cable core is always higher than that of the surface temperature

and the difference of the temperature rise of the cable core is not obvious when the harmonic content is lower than 20%

while the difference of the temperature rise is significantly increased when the harmonic content exceeds 20%.This study can provide a theoretical basis for the thermal performance evaluation and life prediction of cables under harmonic environment.