How to select Current Transformer Core?
The basic structure of the current transformer is mainly composed of a primary winding, a secondary winding and an iron core, and there is insulation between the primary, secondary and iron cores. The simplest current transformer has a primary winding, a secondary winding and an iron core. Such a current transformer also has only one current ratio. In order to improve the accuracy of the current transformer, the error of the current transformer is generally compensated. In this way, in addition to the above-mentioned primary and secondary windings and iron cores, some additionally wound auxiliary coils or add auxiliary iron cores.
For high-voltage current transformers above 10KV, for the convenience of use, several independent transformer core windings are often installed on a transformer through a common primary winding, insulation and shell to make multiple current transformers. In this way, one current transformer is equivalent to two or three transformers, and two or three secondary ones can be used for measuring or protecting lines respectively.
Precision current transformers of class 0.2 and above are generally made of multiple current ratios, that is, a transformer has many current ratios, which can be selected for use. Formula, if the primary (or secondary) winding is unchanged, corresponding to each tap winding of the secondary (or primary), a current ratio is obtained. Such primary and secondary winding combinations, there are many current ratios. The iron core of the current transformer has two forms: square and circular:
Square, that is, laminated. A square iron core is formed by stacking silicon steel sheets one by one. The advantage of this core is that the coil is easy to wind, the winding can be pre-wound on the machine, and then put on the silicon steel sheet iron core to become the winding; And lamination and installation are more troublesome.
Ring-shaped, ring-shaped iron cores are made of silicon steel sheets punched into rings and stacked one by one at the beginning, and most of them are now directly rolled iron cores with silicon steel sheets. The advantages of this core are that there is no air gap, high magnetic performance, and it is easy to roll. If the winding is wound, the leakage flux is very small. Therefore, precision current transformers above class 0.2 use this tape-wound core. Its disadvantage is that it is difficult to wind windings, especially thick wire windings, and it is not easy to achieve mechanized winding.
The basic structure of the current transformer is mainly composed of a primary winding, a secondary winding and an iron core, and there is insulation between the primary, secondary and iron cores. The simplest current transformer has a primary winding, a secondary winding and an iron core. Such a current transformer also has only one current ratio. In order to improve the accuracy of the current transformer, the error of the current transformer is generally compensated. In this way, in addition to the above-mentioned primary and secondary windings and iron cores, some additionally wound auxiliary coils or add auxiliary iron cores.
For high-voltage current transformers above 10KV, for the convenience of use, several independent transformer core windings are often installed on a transformer through a common primary winding, insulation and shell to make multiple current transformers. In this way, one current transformer is equivalent to two or three transformers, and two or three secondary ones can be used for measuring or protecting lines respectively.
Precision current transformers of class 0.2 and above are generally made of multiple current ratios, that is, a transformer has many current ratios, which can be selected for use. Formula, if the primary (or secondary) winding is unchanged, corresponding to each tap winding of the secondary (or primary), a current ratio is obtained. Such primary and secondary winding combinations, there are many current ratios. The iron core of the current transformer has two forms: square and circular:
Square, that is, laminated. A square iron core is formed by stacking silicon steel sheets one by one. The advantage of this core is that the coil is easy to wind, the winding can be pre-wound on the machine, and then put on the silicon steel sheet iron core to become the winding; And lamination and installation are more troublesome.
Ring-shaped, ring-shaped iron cores are made of silicon steel sheets punched into rings and stacked one by one at the beginning, and most of them are now directly rolled iron cores with silicon steel sheets. The advantages of this core are that there is no air gap, high magnetic performance, and it is easy to roll. If the winding is wound, the leakage flux is very small. Therefore, precision current transformers above class 0.2 use this tape-wound core. Its disadvantage is that it is difficult to wind windings, especially thick wire windings, and it is not easy to achieve mechanized winding.