The Sdudy Of Geomagnetic’s Impact On The Protection Current Transformer

The sun is a star holds enormous energy; its internal occurs drastic changes and releases energy every minute. As eleven years for a cycle, it will enter a surface activity exuberant period, in this period, with the sun internal acuteness activity, a large number of X ray, ultraviolet, visible light and high-energy proton and electron beam will be cast into the space, if this kind of charged particle was cast out just positive for earth, finally reach the earth near, it will impact the earth’s own magnetic field, causing severe fluctuation of the geomagnetic field, this feature known as geomagnetic storm. If the geomagnetic storm is large enough, it can cause the operation of the power system face to threat. As one important part of the protection device in order to ensure the power system’s safe and stable operation, whether the current transformer can transform the fault current from the first side to the secondary side accurately, becomes very important. This paper, combined the equivalent circuit of transformer and the characteristics of geomagnetic induced current (GIC) which is induced by the geomagnetic storm, through the basis theoretical analysis, then choose the suitable current transformer’s simulation model and make the simulation, its conclusion is the current transformer’s core will become saturation under the geomagnetic storm. So it will affect the normal work of the current transformer, threatening the security of the system. This conclusion can provide some important reference information for the related departments in the future when they do some power grid planning. In addition, in order to be able to take some corresponding measures on the transformer core saturation, need to accurately and fast detection method, based on the three order difference method, found it existing some disadvantages and made some corresponding improvements, this paper proposes a new current transformer core saturation detection method. Upon examination, the new method can really make up for the deficiency of the finite difference method and reach the desired effect.