The space magnetic fields（MFs） generated by dry-type air-core reactors have become the main source of electromagnetic contamination in substations. Thus

we estimated the distribution of the MFs accurately based on scaled experiments. Firstly

we summarized the theoretical scaling rules of the air-core reactors’ parameters

and proposed the corresponding modification strategies for three typical circumstances on the premise that the magnetic induction intensity around the air-core reactor remained unchanged. Secondly

we measured the MF distributions of a half-size model and a one-sixth-size model in axial and radial directions by the modification strategies

and found that the results were generally in accordance with the corresponding MFs of the original model

verifying the scaling rules

as well as the equivalency of the scaled experimentation. Thirdly

we proposed six simplified models of air-core reactors composed of one-loop

two-loop

and three-loop toroidal conductors to simplify the estimation. Further experiments indicate that

compared with the original model

the two-loop configuration of structure 1 with its two toroidal current-carrying conductors being placed at 1/3 and 2/3 of the reactor height

respectively

is the most accurate.