Iron core structure, saturation type current limiter and reactor

The invention discloses an iron core structure, a saturation type current limiter and a reactor. The iron core structure comprises an excitation segment, a working segment and a magnetic guide segment, wherein the excitation segment, the working segment and the magnetic guide segment form a closed shape, the magnetic conductivity of the excitation segment is a first preset value, the magnetic conductivity of the magnetic guide segment is a second preset value, the magnetic conductivity of the working segment is a third preset value, and the second preset value is larger than the third preset value and is smaller than or equal to the first preset value. The magnetic conductivity of the excitation segment is maximum and the magnetic conductivity of the working segment is minimum, thus, the excitation segment is not liable to enter a saturation state, the magnetic leakage of the iron core structure is reduced, the magnetic flux conductivity of the iron core structure is improved, and the working segment is liable to further enter a saturation state and reaches a certain saturation degree. By the iron core structure, the possibility that the normal running of a power grid applying a saturable reactor or the saturation type current limiter is affected by the influence on the function of the saturation type current limiter and the saturable reactor since the working segment does not reach a certain saturation degree is reduced.