Search

In order to reduce the vibration of shunt reactors with gapped iron-core structure, accurate stress computation should be carried out. The magnetization and magnetostrictive anisotropy should be considered in the calculation. In this paper, the magnetization and magnetostrictive properties of non-oriented silicon steel sheets along the rolling direction and the transverse direction are first measured by a magnetization and magnetostriction tester. Based on the measurement results, an electromagneto–mechanical coupled numerical model for shunt reactors, considering magnetization and magnetostrictive anisotropy, has been developed. Then, the stress distribution of the reactor core is calculated and that between isotropy and anisotropy numerical model is compared. From the computation results, it can be seen that magnetization and magnetostrictive anisotropy greatly influences the stress distribution of the reactor core.

Magnetically controlled saturable reactors (MCSRs) are widely used in high voltage power system, but they make larger vibration and noise than transformers and other types of reactors due to the gapped iron-core structure and magnetic saturation. The main reasons of MCSR vibration are magnetostrictive effect of silicon steel sheet and electromagnetic force between core discs. This paper studies the influence of these two kinds of forces on MCSR vibration, which will be used to help seek new vibration reduction method. Firstly, because MCSRs work in DC bias conditions, multigroup magnetic and magnetostrictive characteristics of silicon steel sheet considering anisotropy under different DC bias excitation conditions are tested. Secondly, based on energy variation principle and virtual work principle, an electro-magneto-mechanical coupled numerical model for MCSRs is established. In order to compare the influence of magnetostrictive effect with electromagnetic force effect on MCSR vibration, vibration accelerations caused by magnetostrictive effect, electromagnetic force and the combination of them are calculated, respectively. From the computation results, it can be seen that the total acceleration is not simple superposition of electromagnetic acceleration with magnetostrictive acceleration. Finally, vibrations of a MCSR under different practical working conditions are tested to prove the validity of the proposed model.

The dependencies of displacement on current under different variable loads for giant magnetostrictive actuators are computed by using the finite-element method and measured. It is found that the computed result is in agreement with the measured one. This indicates that the finite-element model is valid for computing the displacement for actuators under variable load, and it can be used to design actuators.