Comparison between Current Transformer and Voltage or Potential Transformer
Comparison between Current Transformer and Voltage or Potential Transformer
Current Transformer (CT) | Potential Transformer (PT or VT) |
CT step-down the high current to the safe level of current. | PT step-down the high voltage levels to the safe level of voltage. |
Symbol of CT | Symbol of PT or VT |
Its primary winding is connected in series with the line to be measured. | Its primary is connected in parallel to the line to be measured. |
It has a fewer number of turns in its primary winding. | It has a large number of turns in its primary winding. |
It has a large number of turns in the secondary winding. | It has few numbers of turns in the secondary winding. |
Its secondary cannot be open circuit. | Its secondary can be open circuit. |
It has a very high turn ratio. | It has a very low turn ratio. |
Its accuracy does not depend on the secondary burden (numerous ammeters can be connected to output). | Its accuracy depends on the secondary burden and causes an error when numerous voltmeters are connected. |
The primary winding contains full line current. | The primary windings contain full line voltage. |
Current transformer can be either wound type or core type. | The potential transformer can be either electromagnetic or capacitor voltage type. |
The primary current does not depend on the secondary current. | The primary current depends on the secondary current. |
It is a step-up transformer. | It is a step-down transformer. |
It is used for measurement and monitoring of current in high power lines. | It is used for the measurement of high voltage in power lines. |
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