What is a Current Transformer? Technical Knowledge

You may have wondered how is it possible to check the current flowing in the three-phase lines, as the current is of large quantity and the standard meters do not operate at high currents. So, to measure the current, a device called a current transformer is used.

What is a Current Transformer?

A current transformer is a type of instrument transformer that is used to measure the current in an electrical circuit. It is designed to produce a reduced current in its secondary winding proportional to the current flowing in its primary winding. This reduced current can then be sent to a measuring or control device which is capable of handling lower currents than those in the circuit being measured.

We will learn about the concept of current transformer in this article.

Current Transformer Explanation

A current transformer is a type of instrument transformer that is used to measure the current in an electrical circuit. It is designed to take a large current from the primary circuit, and transform it into a smaller current in the secondary circuit.

This secondary current is then sent to a measuring or control device, which can measure and control the current in the primary circuit. Current transformers are used in a variety of applications, including power distribution and control systems, power generation and transmission, and electrical instrumentation.

Current Transformer with Example

A current transformer is a type of instrument transformer used to measure the current in an electrical circuit. It is designed to take a large current from the primary circuit and transform it into a smaller current in the secondary circuit.

For example, a current transformer with a 1000:5 ratio would take a large current of 1000 amperes in the primary circuit, and transform it into a smaller current of 5 amperes in the secondary circuit. This secondary current can then be sent to a measuring or control device, which can measure and control the current in the primary circuit.

Current Transformer in Energy Meters

Current transformers are commonly used in energy meters, which are devices used to measure and monitor the power consumption of a home or business. The current transformer measures the current in the circuit and sends it to the meter, which then calculates the amount of energy being used.

The current transformer ensures that the meter is measuring the correct amount of current, and it also helps to protect the meter from power surges and other electrical problems.

Current Transformer is made up of

A current transformer typically consists of two coils of wire, a primary and a secondary. The primary coil is connected to the circuit being measured and carries the full current of the circuit.

The secondary coil is connected to a measuring or control device and carries a reduced current proportional to the current flowing in the primary coil. The transformer also contains a magnetic core, which helps to concentrate the magnetic field and ensure that the transformer operates efficiently.

What is S1 and S2 in current transformer?

S1 and S2 are the primary and secondary windings of the current transformer. The primary winding, or S1, is connected to the circuit being measured, and carries the full current of the circuit. The secondary winding, or S2, is connected to a measuring or control device and carries a reduced current proportional to the current flowing in the primary winding.

What Happens if Energy Meter and Current Transformer Ratio Mismatch

If the energy meter and current transformer ratio mismatch, the readings from the meter may be inaccurate. This is because the current transformer will be sending a reduced current to the meter that is not proportional to the current in the primary circuit. This can result in the meter displaying incorrect readings or not functioning properly. To avoid this, it is important to ensure that the energy meter and current transformer have the same ratio.

The Ratio of Current Transformer

The ratio of a current transformer is the ratio of the primary current to the secondary current. This is usually expressed as a ratio of the primary current to the secondary current, such as 1000:5. This means that for every 1000 amps of current in the primary circuit, the current transformer will produce 5 amps of current in the secondary circuit. The ratio of a current transformer is important because it determines how much current is sent to the measuring or control device, and thus how accurately the device can measure and control the current in the circuit.

Current Transformer Formula and its Explanation

The current transformer formula is used to calculate the secondary current of a current transformer.

It is written as Isec = Iprimary x ratio,

where Isec is the secondary current, Iprimary is the primary current, and ratio is the ratio of the current transformer. This formula shows that the secondary current is proportional to the primary current, meaning that if the primary current is increased, the secondary current will also increase.

This formula is useful for determining the amount of current that will be sent to a measuring or control device, and for ensuring that the device is capable of handling the current.

Current Transformer Formula Example

For example, if a current transformer has a ratio of 100r:5, and the primary current is 2000 amps, then the secondary current can be calculated using the current transformer formula.

Isec = Iprimary x ratio, so Isec = 2000 x 0.005 = 10 amps.

This means that the current transformer will send 10 amps of current to the measuring or control device, which can then be used to measure and control the current in the primary circuit.

Current transformer important 10 Technical points To Remember

1. A current transformer is a type of instrument transformer used to measure the current in an electrical circuit.
2. It is designed to take a large current from the primary circuit and transform it into a smaller current in the secondary circuit.
3. Current transformers are commonly used in energy meters to measure and monitor the power consumption of a home or business.
4. The ratio of a current transformer is the ratio of the primary current to the secondary current.
5. The current transformer formula is used to calculate the secondary current of a current transformer.
6. The secondary current is proportional to the primary current, meaning that if the primary current is increased, the secondary current will also increase.
7. Current transformers are used in a variety of applications, including power distribution and control systems, power generation and transmission, and electrical instrumentation.
8. It is important to ensure that the energy meter and current transformer have the same ratio to avoid incorrect readings.
9. Current transformers typically consist of two coils of wire, a primary and a secondary, and a magnetic core.
10. Current transformers are essential for measuring and controlling the current in an electrical circuit.

Current Transformer Advantages and Disadvantes

Current Transformer Real Life Examples

1. Current transformers are commonly used in power distribution and control systems to measure and control the current in the circuit.
2. They are also used in power generation and transmission systems to monitor and regulate the current in the circuit.
3. In electrical instrumentation, current transformers are used to measure the current in a circuit and send the reduced current to a measuring device.
4. Current transformers are also used in energy meters to measure and monitor the power consumption of a home or business.

Where should not use Current Transformer?

Current transformers should not be used in circuits that carry DC current, as they are designed to measure AC current. Additionally, current transformers should not be used in circuits with high power surges, as these can damage the transformer or the measuring device.

10 General Question most asked about Current Transformer?

1. What is a current transformer?
2. What is the ratio of a current transformer?
3. What is the current transformer formula?
4. What is the purpose of a current transformer?
5. What is the difference between a current transformer and a voltage transformer?
6. What are the advantages and disadvantages of current transformers?
7. What are the components of a current transformer?
8. Where should current transformers not be used?
9. What is the difference between S1 and S2 in a current transformer?
10. What are some real-life examples of current transformers?

10 Technical question most asked about current transformer in engineering interview?

1. What is the operating principle of a current transformer?
2. What are the safety measures to be taken while installing a current transformer?
3. How is the ratio of a current transformer calculated?
4. How is the accuracy of a current transformer determined?
5. How is the output voltage of a current transformer determined?
6. What is the role of the magnetic core in a current transformer?
7. How is the current in a current transformer measured?
8. How is the phase angle of a current transformer determined?
9. How is the phase shift of a current transformer determined?
10. What are the different types of current transformers?

What technical research is on going on current transformer?

Research into current transformers is ongoing in order to improve their accuracy, efficiency, and safety. New materials and technologies are being investigated to make current transformers more efficient and accurate. Smart current transformers that can automatically adjust their ratios based on the current in the primary circuit are also being developed. Additionally, research is being done to reduce the cost of manufacturing current transformers, as well as to improve their safety features, accuracy, and response times. Research is also being done into the effects of power surges on current transformers, as well as into ways to make them smaller and more durable. Finally, new ways to protect current transformers from power surges and other electrical problems are being investigated. All of this research is aimed at making current transformers more reliable and efficient, so that they can be used in a variety of applications.

Top Brands list those are manufacturing Current transformer

1. ABB
2. Schneider Electric
3. Siemens
4. Eaton
5. GE
6. L&T
7. Crompton Greaves
8. Fuji Electric
9. Omron
10. Toshiba

Authentic link for Research Study on Current Transformer

1. https://www.sciencedirect.com
2. https://www.journals.elsevier.com
3. https://ieeexplore.ieee.org
4. https://www.hindawi.com
5. https://ieeexplore.ieee.org