How to check the multiple of current transformer?

The multiple of current transformer is usually expressed by its transformation ratio, which reflects the proportional relationship between the primary current and the secondary current of the transformer.
Current transformer is an important device commonly used in power system, which is used to convert high current into low current for measurement, protection or control equipment. In practical applications, since the primary current is often large, direct measurement is not only difficult but also dangerous, so it is necessary to reduce it proportionally through current transformer. The "multiple" or "ratio" here refers to the ratio between the primary current and the secondary current.
For example, a current transformer with a transformation ratio marked as 100/5 means that when 100 amperes of current flows through the primary side, the secondary side will output 5 amperes of current. Here, "100" represents the rated current of the primary side, "5" represents the rated current of the secondary side, and the multiple or ratio is 100 divided by 5, that is, 20 times. In this way, by measuring the small current on the secondary side, the large current value on the primary side can be inferred.
In actual operation, the multiples of current transformers can usually be checked in the following ways: first, directly check the nameplate or label on the transformer body, which usually clearly marks the ratio information; second, consult the relevant equipment technical documents or materials, which will list the technical parameters of the transformer in detail, including the ratio; third, use professional testing equipment to test the transformer, measure the current values ​​on the primary and secondary sides, and calculate the actual ratio. However, this method requires professional knowledge and equipment, and is generally suitable for occasions such as equipment acceptance or troubleshooting.