To ensure that the current transformer provides accurate measurements under normal conditions and limits error during overcurrent situations to protect the connected instruments, two common methods are typically employed.
First, when the number of ampere-turns is low but high measurement accuracy is required, materials with high initial permeability and low saturation magnetic density—such as permalloy or ultrafine crystal alloys—are commonly used for the core. This helps maintain a lower safety factor for the instrument while ensuring precision during regular operation.
Second, for transformers with a high number of turns where the measuring winding cannot meet the required safety factor, an auxiliary transformer can be connected in parallel to the secondary circuit. This auxiliary device acts like a saturable reactor, offering high impedance at rated secondary current but low resistance under higher fault currents. As a result, it allows a sharp increase in current through itself, reducing the current flowing into the secondary load and protecting the instrumentation. However, careful selection of the auxiliary transformer is essential to ensure that it does not compromise the accuracy of the main measuring transformer during normal operation.
These techniques are widely used in power systems and industrial applications to ensure reliable and safe operation of current measurement devices, especially under abnormal or overcurrent conditions.
Rf Connection Cables,Waterproof Sma Connector,Sma F Connector,Sma Connector Types
Dongguan Zhuoyuexin Automotive Electronics Co.,Ltd , https://www.zyx-fakra.com