Search results

The purpose of this paper is to solve the reactive power adjustment and the overvoltage suppression problems in the extra high voltage (EHV) long distance grid, which often appears transient overvoltage, light load loss and other issues.

One 800 kV EHV magnetically saturation controllable reactor (MSCR) used self-power supply control system is designed. The structure and the working mechanism of the novel MSCR are analyzed in detail. Then the control and capacity step adjustment characteristics are obtained by experiments. The harmonic characteristic is studied by theoretical analysis and low voltage test.

To solve the problem of harmonics in the working current of nets windings, the fifth and the seventh filers are equipped between the compensation windings and the control system. The effectiveness of the harmonic suppression method is proved by simulation and experiments.

It proves that the 800 kV EHV MSCR design in this paper can achieve the purpose of the reactive power continuous linear adjustment, and the capacity adjustment is sensitive. After filtering, the harmonics level of the working current meets the standard of the EHV grid.

A simplified method for calculating iron loss of three-phase transformer is proposed in this paper. The rotating iron loss measured from 2-D vector magnetic property measurement system of gain-oriented silicon steel sheet can be taken into account in this method. The paper aims to discuss these issues.

The finite element analysis formulation is combined with the magnetic reluctivity model expressed by diagonal tensor for 2-D nonlinear and anisotropic magnetic problem, while the iron loss is computed in terms of the interpolation of rotational loss curves measured under various loci of controlled magnetic flux density B.

The iron loss of three-phase transformer is obtained by the proposed method. And the calculating iron loss is verified with experimental results.

The method presented in this paper enables the iron loss of three-phase transformer to be more accurately calculated and more easily applied, considering the rotational iron loss.

The magnetostriction of grain-oriented electrical silicon steel sheet is studied for the magnetic field direction along the rolling direction and deviating from it. The method of calculating the vibration of transformer is developed through COMSOL. The paper aims to discuss these issues.

Measurements of signals of magnetostriction and magnetic polarization, and calculation through software.

The angle between the magnetic field direction and the rolling direction does a great influence on magnetostriction strain.

The maximum λ _p-p of transversal magnetostriction is above 30 times more than the value when the angle is 0°. The transversal magnetostriction is a main reason of vibration increasing at the corner of transformer.