# CT and PT | What is CT and PT | Difference Between CT and PT

In this post, we will learn what CT and PT are and why CT is needed in the electrical system of PT. how to work CT PT transformer

## What are CT and PT?

Friends, if you ever ask about an instrument transformer in an interview, you should keep in mind that CT and PT are both instrument transformers.

### Full form of CT and PT

CT- Current Transformer

PT- Potential Transformer

CT and PT is both a transformer. Because of this, they can be used only in AC supplies.

### What is CT and PT

CT and PT These are both measuring devices. A measuring device means that we use both of these to measure current and voltage.

We use CT and PT, where a lot of current and voltage is used.

The work of CT and PT: We have to give some parameters by reducing the high voltage and high current. With the help of those parameters, we can easily measure the voltage and current flowing at a large scale.

### What is CT

CT means current transformer. The task of which is to reduce the excess current flowing in the electrical system.

#### Why use the current transformer

Whenever there is a lot of current flow in a system, then applying the current to the primary means that CT is applied to determine how much current is going on.

We cannot use the clamp meter here. Because every device has a limit, how much current can be checked on it?

Because of this, where we have to check more current, there is only one device. Whose name is CT means current transformer?

If you have ever checked the AC with a clamp meter, let me know. The clamp is whistled above the meter. With the help of that whistle, we check the current. But this whistle is tiny; its limit is also meagre. Because of this, we cannot use it in an extensive line.

### How to work CT

All current transformers have a ratio, which we call the CT ratio. We know that the city reduces the current, so to find out how much current this city will give us, a ratio is written on the city called the CT ratio.

### What is the CT ratio?

With the help of the whistle ratio, we can know how much current our whistle is reducing.

For example- e.g. there is a current transformer whose CT ratio is 1000/5. This means that when 1000 amperes current is coming out of the system. Then CT will give us output by converting that 1000 amperes to 5 amperes.

And if we have installed a 1000/1 ratio city in our system, it will send 1000 amperes flowing in the city wire from the output wire to 1 ampere.

The full name of PT is the potential transformer. Now all the whistles we told you about, PT also does the same thing. But PT does all of that with voltage.

## How to work PT

A potent transformer reduces the high voltage and gives us a lower voltage in the output. PT is used in the high transmission line. Because very high voltage is used in the transmission line.

Like – we know that from any voltmeter 33 kilovolts or even more than 2 lakh 20 thousand KV, we cannot check this much voltage. So at this time, we use PITI to convert that high voltage into a low voltage, and later on, we will be able to measure the voltage coming out of the PT with the help of a voltmeter.

### What is the PT ratio?

Just as the CT ratio is written on CT, the PT ratio is also on PT, which is called the PT ratio.

For example, a CT of 1000/1 converts 1000 amperes to 1 ampere. Similarly, PT also has a ratio. If there is a pit and its ratio is 11000/110, then the output comes out by changing the PT 11000 voltage to 110 voltage.

## Difference between CT and PT

• Current transformers use CT to measure the current value, while potent transformer PT is used to measure voltage.
• The PT is coupled to the system in parallel, while the CT is added to the series.
• The CT RATIO comes in a range of 1 ampere and 5 amperes, while the PT RATIO comes in a range of 110 voltages.
• The output parameters derived from CT are combined with an ampere meter, while the output of PT is combined with a voltmeter.
• PT is a step-down transformer, while CT is a step-up transformer.

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