Bus type current transformer is a low-voltage indoor current transformer with bus type cast insulation and plastic casing insulation, commonly known as a through core current transformer. Current transformers are widely used in low-voltage systems for measurement, energy metering, and relay protection circuits. They can be directly used as primary windings with current carrying conductors passing through window holes and the number of winding turns can be changed as needed to adapt to circuits with different rated currents. They are flexible and convenient to use, and due to their simple structure, small size, and low price, they have been widely used

Matching current transformers with energy meters

In order to improve the accuracy of electric energy metering devices, it is generally required that the primary rated current of the busbar type current transformer used in the energy meter should be above 150A. When it is below 150A, a direct connection type energy meter can be selected. When using a load current of 50-150A, due to the still large load current, improper selection of the inlet and outlet wire cross-section of the energy meter or poor contact of the wiring terminal wire of the energy meter can easily burn out the coil or terminal box of the energy meter. So when the load current is between 50-150A, a busbar type current transformer can be used in conjunction with an energy meter.

Improvement of Busbar Current Transformer
The development of rural electricity is rapid, but it is affected by various factors, resulting in poor load stability and significant disparities. This situation increases the difficulty of correct measurement. The current transformer is selected according to the Nameplate capacity of the Distribution Transformer. When the load is light, the current transformer needs to be replaced or the number of primary turns needs to be changed. Once the load increases, it needs to be restored, which is very troublesome in practical operation.
Based on long-term work experience, combined with local conditions, and in cooperation with manufacturers, the following improvements have been made on the basis of the original current transformer: the original busbar current transformer has only one ratio designed to two ratios, and the secondary wiring terminal has been changed from the lower side to the original trademark on the upper side. In this way, when the load changes, simply replacing the secondary wiring terminal of the current transformer can solve the transformation ratio problem, and the wiring is very convenient.