Potential Transformer (PT)

Definition – The potential transformer may be defined as an instrument transformer used for the transformation of voltage from a higher value to the lower value. This transformer step down the voltage to a safe limit value which can be easily measured by the ordinary low voltage instrument like a voltmeter, wattmeter and watt-hour meters,…

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Current Transformer (CT)

Definition: A current transformer is a device that is used for the transformation of current from a higher value into a proportionate current to a lower value. It transforms the high voltage current into the low voltage current due to which the heavy current flows through the transmission lines is safely monitored by the ammeter. The…

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Back-to-Back Test (Sumpner’s Test) on Transformer

Definition: The full load test on a small transformer is very convenient, but on large transformer, it is very difficult.The maximum temperature rise in a large transformer is determined by the full load test.This test is called, back-to-back test, regenerative test or sumpner’s test. The suitable load which absorbs the full load power of a…

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Booster Transformer

Booster transformer is one which is often used towards the end of a power line to raise the voltage to the desired value. It is used for controlling the voltage of a feeder at a point far away from the main transformer. The secondary of the booster transformer is connected in series with the line,…

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Parallel Operation of a Single Phase Transformer

Parallel Operation of a Single Phase Transformer means that the two or more transformers having same polarities, same turn ratios, same phase sequence and the same voltage ratio are connected in parallel with each other. The circuit diagram of two single phase transformer A and B connected in parallel are shown below Let, a1 is…

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Parallel Operation of a Transformer

The Transformer is said to be in Parallel Operation when their primary windings are connected to a common voltage supply, and the secondary windings are connected to a common load. Contents: Reasons For Parallel Operation Necessary Conditions For Parallel Operation Reasons For Parallel Operation Parallel operation of a transformer is necessary because of the following…

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Types of Transformer

There are various types of transformer used in the electrical power system for different purposes, like generation, distribution and transmission and utilization of electrical power. The different types of transformer are Step up and Step down Transformer, Power Transformer, Distribution Transformer, Instrument transformer comprising current and Potential Transformer, Single phase and Three phase transformer, Auto…

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Power Triangle

Power Triangle is the representation of a right angle triangle showing the relation between active power, reactive power and apparent power. When each component of the current that is the active component (Icosϕ) or the reactive component (Isinϕ) is multiplied by the voltage V, a power triangle is obtained shown in the figure below The…

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Cooling of Transfomer and Methods of Cooling

Cooling of Transformer is the process by which heat generated in the transformer is dissipated or treated to the safe value. This is achieved by various cooling methods of transformer available. The major factor for the generation of heat in the transformer is the various losses like hysteresis, eddy current, iron, and copper loss. Among…

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Open Circuit and Short Circuit Test on Transformer

In order to determine the parameters of a transformer such as voltage regulation and efficiency, the following two tests are carried out. Contents: Open Circuit Test Calculation of Open Circuit Test Short Circuit Test Calculation of Short Circuit Test Open Circuit Test The Open circuit test is carried out to determine the no-load loss or…

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