Electromagnetic environment measurements in substations and transmission lines are crucial for assessing environmental factors in power facilities.The accuracy and reliability of these measurements are paramount

and the associated uncertainty is a key parameter for quantitatively evaluating the quality of results.This paper addresses the challenge of the uncertainty assessment in electromagnetic environment measurement for AC transmission and transformation projects.First

the measurement method of the electromagnetic environment is outlined.Next

the assessment models for evaluating the uncertainty of these measurements are established

including Class A and Class B evaluation models.Lastly

based on practical examples

the evaluation and calculation processes for the uncertainty of the measurement related to power frequency electric fields and magnetic induction intensities are presented respectively.The methods discussed in this paper can be extended to assessing the uncertainty in electromagnetic environment measurements in various scenarios

such as communication base stations and radars.