Which device is used to step down current for metering and protection applications?

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Multiple Choice

Which device is used to step down current for metering and protection applications?

Explanation:
Current transformers are used to step down current to a safe, standard level for metering and protection. They pass the high primary current through a winding and produce a much smaller, proportional current on the secondary, which meters and relays can handle. The secondary current is related to the primary by the turns ratio, providing isolation between the high-energy circuit and measuring equipment. For example, a CT with a 200:5 ratio turns 200 A on the primary into 5 A on the secondary, allowing accurate, safe measurement or protection signaling. Other devices, like potential transformers, are for voltage, power transformers are for general power transfer, and autotransformers aren’t the typical choice for metering/protection current signals.

Current transformers are used to step down current to a safe, standard level for metering and protection. They pass the high primary current through a winding and produce a much smaller, proportional current on the secondary, which meters and relays can handle. The secondary current is related to the primary by the turns ratio, providing isolation between the high-energy circuit and measuring equipment. For example, a CT with a 200:5 ratio turns 200 A on the primary into 5 A on the secondary, allowing accurate, safe measurement or protection signaling. Other devices, like potential transformers, are for voltage, power transformers are for general power transfer, and autotransformers aren’t the typical choice for metering/protection current signals.

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