Difference WikiPhysics

Difference Between Current Transformer and Voltage Transformer

Main Difference

The main difference between the Current Transformer and Voltage Transformer is that the Current Transformer is the transformer that converts the high value of current into low value, whereas Voltage Transformer changes the high-value voltage into low value.

Current Transformer vs. Voltage Transformer

A current transformer is the type of transformer that changes the current of high value into low value. On the other side, the voltage transformer is the type of transformer that changes the high-value voltage into low value. There is no other name for the current transformer whereas; voltage transformer is also known as the potential transformer.

The core of the current transformer is made up of silicon steel, while that of the voltage transformer is composed of high-quality steel and works at low flux density. Current transformer connected with the circuit in the form of series. Thus, full line current passes through the winding. On the flip side, a voltage transformer connected with the circuit in parallel form. That is why full line voltage passes across the winding.

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There are few turns in the primary twisting or winding of the current transformer, while the secondary twisting or winding shows a large number of turns. On the other hand, the primary winding of the voltage transformer has a large revolution number, but its secondary winding takes a few revolutions. So, the current transformer is a type of step-up transformers, while the voltage transformer is a type of step down transformer.

The current transformer has two types, i.e., closed core and wound core. On the other hand, the voltage transformer also has two types, i.e., electromagnetic type and capacitor voltage type. In a current transformer, flux density and excitation current vary over a wide range while it varies within a narrow range in voltage transformer.

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The current transformer is used to measure current and power, to operate the protective relay and to monitor the power grid operation, etc. On the other side, the voltage transformer is used for measurement, as the power source and to operate a protective relay, etc.

ComparisonChart

Current TransformerVoltage Transformer
A type of transformer that converts the high value of current into a low value is known as the current transformer.The type of transformer that converts the high value of voltage into a low value is known as the voltage transformer.
Also Known As
There is no other name for the current transformer.The voltage transformer is also known as a potential transformer.
Connection Pattern
A current transformer is connected with the circuit in the form of series.The voltage transformer is connected with the circuit in parallel form.
Core
Its core is made up of silicon steel lamination.Its core is composed of high-quality steel and works at low flux density.
Number of Turns in Primary Circuit
There are few turns in the primary circuit of the current transformer.The primary circuit of the voltage transformer has more turns.
Number of Turns in Secondary Circuit
Its secondary circuit has a large number of turns.Its secondary circuit has few turns.
Primary Winding
Primary winding carries a current that is to be measured.Its primary winding carries the voltage that is to be measured.
Secondary Winding
The secondary winding has a connection with the current winding of the instrument.The secondary winding of the voltage transformer has a connection with the meter or the instrument.
Range
5A or 1A110v
Transformation Ratio
The current transformer has a high transformation ratio.It shows a low transformation ratio.
Input
The input of this type of transformer is constant or direct current.Its input is a constant or direct voltage.
Burden
It does not depend on the secondary burden.The voltage transformer is based on the secondary burden.
Impedance
Has low impedance.Has a high impedance.
Flux Density and Excitation Current
In a current transformer, flux density and excitation current vary over a wide range.In a voltage transformer, flux density and excitation current vary within a narrow range.
Types
The current transformer has two types, i.e., closed 1core and wound core.The voltage transformer also has two types, i.e., electromagnetic type and capacitor voltage type.
Use
By using a current transformer, an ammeter of 5 Ampere can be used to measure high currents like 200 amperes.With the help of a potential transformer, a voltmeter of 120 V can be utilized to measure high voltages like 11 KV.
Type of Transformer
The current transformer is a type of step-up transformer.It is a type of step-down or backward step transformer.
Primary Current
There is no dependence on primary current on secondary side circuit conditions.In the voltage transformer, the primary current based on secondary side circuit conditions.
Application
The current transformer is used to measure current and power, to operate the protective relay and to monitor the power grid operation, etc.The voltage transformer is used for measurement as a power source and to operate the protective relay, etc.
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What is the Current Transformer?

A current transformer is the type of transformer that changes the current of high value into low value. As it is not easy to calculate high-value line current directly so, it plays its role to decrease the high evaluation of current into a low evaluation, which can easily estimate by the means or instrument. It is mostly referred to as CT and is connected with the circuit in the form of series.

The core of the current transformer is made up of silicon steel lamination. The current transformer has few turns in the primary winding of the current transformer. On the other side, secondary winding shows a large number of turns. As the number of secondary turns is more than the primary so, it is a type of step-up transformer.

Its primary winding is linked to the line whose value is to be measured whereas, its secondary winding is attached to the meter or ammeter, which measures the line value. So, it provides an isolated lower current on its secondary terminals.

In a current transformer, flux density and excitation current vary over a wide range. Moreover, by using the current transformer, an ammeter of 5 Ampere can be used to measure high currents like 200 amperes. It has two types, i.e., closed 1core and wound core, and its range is 5A or 1A.

Current transformers are used to keep an eye on currents at risky high voltages. When the current is within the primary, then the second line of a transformer must not cut off from the load because the secondary will keep on driving or active current into a highly efficient unlimited impedance as long as its insulation breakdown or collapse voltage. Therefore, it gives up operator safety.

This type of transformer decreases high-value currents to reduced value and provides a handy method of checking the specific electric powered current that is moving in an AC transmission line with the help of a standard ammeter. So, it is used to measure current and power, to operate the protective relay and to monitor the power grid operation, etc.

What is a Voltage Transformer?

The voltage transformer is a device that is used to change the high-value voltage into low value. It is also known as a potential transformer. It decreases the voltage of high value into a low value that can easily be calculated by using a meter or the voltmeter. This protected low value of voltage is then provided to the low rating meters and relays.

The key issue of a voltage transformer is composed of high-quality steel that works at low fluence. The primary winding of the voltage transformer has more turns than its secondary winding. That is why it is a type of step down transformer. Its primary terminal is linked with the line to measure the line voltage. On the other side, the secondary winding of the voltage transformer has a connection with the meter or the instrument.

In a voltage transformer, flux density and excitation current vary within a narrow range. Moreover, with the help of a voltage transformer, a voltmeter of 120 V can be utilized to measure high voltages like 11 KV. It also has two types, i.e., electromagnetic type and capacitor voltage type. Its range is 110v.

The voltage transformer is used to step down the voltage in an electrical energy power system. It converts the voltage to a protected value, which is then provided to the low rating meters and relays. As the commercially accessible relays and meters are set for low voltage so, the potential transformer is used to step down the voltage in the distribution systems.

Moreover, it can also be used to step up the voltage. Thus, the voltage transformer plays an important role in transmission lines, where it steps up the voltage to reduce the line losses.

Key Differences

  1. A type of transformer that converts the high value of current into a low value is known as the current transformer whereas, the type of transformer that converts the high value of voltage into a low value is known as voltage transformer.
  2. There is no other name of the current transformer. On the other hand, the voltage transformer is also known as a potential transformer.
  3. The current transformer is connected with the circuit in the form of series. Conversely, the voltage transformer is connected with the circuit in parallel form.
  4. There are few turns in the primary circuit of the current transformer. On the other side, the primary circuit of the voltage transformer has more turns.
  5. The secondary circuit of the current transformer shows a large number of turns while the secondary circuit of the voltage transformer shows few turns.
  6. The primary winding of the current transformer transmits current that is to be measured. On the other hand, the primary winding of the voltage transformer transmits the voltage that is to be measured.
  7. The secondary winding of the current transformer has a connection with the current winding of the instrument whereas, the secondary winding of the voltage transformer has a connection with the meter or the instrument.
  8. The range of the current transformer is 5A or 1A. On the flip side, the range of the voltage transformer is 110v.
  9. The current transformer shows a high transformation ratio, while the voltage transformer possesses a low transformation ratio.
  10. The current transformer has constant current as of its input. On the other side, the input of the voltage transformer is a constant voltage.
  11. The current transformer has no link with the secondary burden. Conversely, a voltage transformer depends on the secondary burden.
  12. The current transformer takes a low impedance. On the other side, the voltage transformer takes a high impedance.
  13. In a current transformer, flux density and excitation current vary over a wide range whereas, in voltage transformer, flux density and excitation current vary within a narrow range.
  14. The current transformer has two types, i.e., closed core and wound core. On the other side, a voltage transformer also has two types, i.e., electromagnetic type and capacitor voltage type.
  15. By using a current transformer, an ammeter of 5 Ampere can be used to measure high currents like 200 amperes. On the flip side, with the help of a potential transformer, a voltmeter of 120 V can be utilized for measuring high potentials or voltages like 11 KV.
  16. A current transformer is a type of step-up transformers while voltage transformer is a type of step down transformers.
  17. A current transformer is used to calculate current and power, to operate the protective relay and to monitor the power grid operation, etc. whereas, voltage transformer is used for measurement, as the power source and to operate a protective relay, etc.

Comparison Video

YouTube video

Conclusion

The above discussion summarizes that the Current transformer is a type of step-up transformer that is used to convert the high value of current into low value. On the other side, the voltage transformer is a type of step down transformer that is used to convert high voltage value into a low voltage value.

Harlon Moss

Harlon currently works as a quality moderator and content writer for Difference Wiki. He graduated from the University of California in 2010 with a degree in Computer Science. Follow him on Twitter @HarlonMoss