Custom Current Sense Transformer

A current transformer (CT) is a special type of transformer, which is a current conversion device. It transforms high-voltage and high-current into lower voltage and small current, supplying it to instruments and relay protection devices, while isolating these instruments and protection devices from high-voltage circuits. A current transformer consists of a closed iron core and windings. The primary winding has very few turns and is connected in series with the circuit where the current needs to be measured. The secondary winding has relatively more turns and is connected in series with measuring instruments and protection circuits. The secondary current of a current transformer is uniformly 5 amperes, making it safe and convenient for measuring instruments and relay protection devices to use. This standardization simplifies the manufacturing process and reduces costs. Therefore, current transformers are widely used in power systems.

Protective current transformers are mainly used in conjunction with relay devices. When faults such as short circuits or overloads occur in the circuit, they provide signals to the relay devices to cut off the fault circuit, thereby protecting the safety of the power supply system. The working conditions of protective current transformers are completely different from those of measuring current transformers. Protective current transformers only start to operate effectively when the current is several to dozens of times higher than the normal current.