| Why Select Current Transformers |
||
| International GB1208-2006 "Current Transformer" stipulates that the rated secondary current standard values are 1A, 2A and 5A. Through practical application, 1A current transformer has many advantages over 5A. When the transmission distance of measurement and protection is large, such as ammeter installation reappearance field, 1A current transformer is preferred. The reasons are as follows: 1. The line power consumption is reduced. The line power consumption is proportional to the square of the passing current. The transformer with the secondary current of 1A is 25 times lower than that of 5A, that is, the power consumption of 1A is only 4% of 5A. When designing a 1A system, it is generally necessary to calculate the impedance of the meter and protect the instrument (ignoring contact resistance). Measuring the power consumption of lines (VA)
2. Increase of transmission distance: The formula S=I 2Z for calculating secondary load of current transformer. Under the same load, the transmission distance of 1A secondary current transformer is 25 times that of 5A, which is advantageous to long-distance measurement and protection.
Transmission distance at different rated capacity (m) 3. Reduction of wire cross-section: In large and medium-sized factories, when the installation distance of instrument and transformer is far (for example, the one-way length is 40m), it can be seen from table 2 that when 5A and 10VA transformers are selected, the wire cross-section needs 4mm, if 1A and 2.5VA transformers are selected, the wire cross-section only needs 1mm. Cross section reduces investment. |
||
|
||
 |
