Current Transformers (CT) ON VIDEO

 

Current Transformers (CT)

According to the definition of the International Electrotechnical Commission, a current transformer is "a measuring transformer in which the secondary current is, under normal conditions of use, practically proportional to the primary current and out of phase with respect to the latter by a angle close to zero for an appropriate direction of the connections1”.

Unlike a voltage transformer, it has the lowest possible impedances: at the primary, to avoid disturbing the current it measures; and at the secondary, to be as close as possible to an ideal current generator.

The notion of "current transformer" is a misnomer, but it has been popularized in the industry. The term “current transformer” is probably more accurate. The abbreviations TC or TI are frequently used.

Although it can be used in the whole range of alternating currents at low frequency, it is generally intended more for the measurement of alternating current at industrial frequency. For direct current, a shunt2 or a Hall effect current sensor must be used.

They are either mounted separately on a clean insulator (see photo), or placed in the domes of the power transformer bushings.

 

Current Transformers (CT)

According to the definition of the International Electrotechnical Commission, a current transformer is "a measuring transformer in which the secondary current is, under normal conditions of use, practically proportional to the primary current and out of phase with respect to the latter by a angle close to zero for an appropriate direction of the connections1”.

Unlike a voltage transformer, it has the lowest possible impedances: at the primary, to avoid disturbing the current it measures; and at the secondary, to be as close as possible to an ideal current generator.

The notion of "current transformer" is a misnomer, but it has been popularized in the industry. The term “current transformer” is probably more accurate. The abbreviations TC or TI are frequently used.

Although it can be used in the whole range of alternating currents at low frequency, it is generally intended more for the measurement of alternating current at industrial frequency. For direct current, a shunt2 or a Hall effect current sensor must be used.

They are either mounted separately on a clean insulator (see photo), or placed in the domes of the power transformer bushings.