In this topic, you study the Difference between Current Transformer (CT) and Potential Transformer (PT).
| S.No | Current Transformer (CT) | Potential Transformer (PT) |
| 1 | The C.T. can be considered as a “series” transformer. The secondary of C.T. cannot be open-circuited, when the primary is connected with line. This may be dangerous to the instrument as well as to the operator. | The P. T. can be considered as a shunt transformer. The secondary of a P. T. can be open-circuited without any damage to the instrument or to the operator. |
| 2 | The primary current of a C.T. is independent of the secondary. | The primary current of a P.T. depends upon the secondary. |
| 3 | The C.T. carries full load current as its primary is connected in series with the line. | The full line voltage works across primary of the P.T. |
| 4 | The excitation of C. T. vary over wide limits. | The excitation ofa P.T. varies over restricted limits. |
| 5 | The secondary of a C. T. should never be open circuited. | There is no danger if secondary of a P. T. is kept open-circuited. |