How does the winding configuration of a wound CT differ from other CTs?

The correct response highlights that a wound current transformer (CT) is characterized by having both a primary and secondary winding. This configuration is crucial for its operation, as it allows the transformer to accurately measure the current flowing through the primary winding while producing a proportional current in the secondary winding for metering or protection purposes.

In contrast to other current sensing devices that may only have a single winding or a different configuration, the presence of both windings in a wound CT enables it to function effectively across a range of applications, providing important benefits such as improved accuracy and the ability to handle larger currents. This dual winding configuration is essential for isolating the measurement circuit from high voltages and ensuring safety in electrical systems.

The other options do not correctly capture the essential characteristics of a wound CT. For instance, a lack of a primary winding would significantly impair its functionality, while high voltage applications are typically not the primary use case for this type of transformer. Lastly, while current ratios can vary in CTs, they do not distinctly define the configuration of wound CTs compared to other designs. Therefore, understanding the dual winding configuration is fundamental to recognizing how wound CTs operate effectively in electrical systems.