How do current transformers (CT) function in switchgear?

Current transformers (CT) are integral components used in switchgear systems primarily for the purpose of measuring voltage and current levels accurately. They function by producing a secondary current proportional to the primary current flowing through their primary winding. This allows for safe monitoring of electrical current levels, which is crucial for both operational management and protective relay systems within the switchgear.

The measured current can then be used for various applications such as display on meters, control circuits, and protection schemes. By providing a scaled-down replica of the high current in the primary system, CTs enhance safety for operators, allowing them to assess current levels without direct exposure to high currents.

The other options do not accurately describe the primary function of current transformers. They do not limit voltage, automatically disconnect faulty circuits, or increase current; rather, their sole purpose within switchgear is to facilitate accurate current measurement which aids in monitoring and protection strategies in electrical distribution systems.