Transformer

A transformer is a passive electrical device that transfers electrical energy from one electrical circuit to one or more circuits. A varying current in any one coil of the transformer produces a varying magnetic flux, which, in turn, induces a varying electromotive force across any other coils wound around the same core.

Working Principle of Transformer

A transformer is a static piece of equipment used either for raising or lowering the voltage of an AC supply with a corresponding decrease or increase in current. It essentially consists of two windings on a common laminated magnetic core. Primary

Continue Reading

Why Transformers are Rated in kVA, Not in kW?

Transformer rating is expressed in kVA, not in kW.  Rating of a transformer or any other electrical machine reflects its load carrying capability without overheating. Temperature rise (a major threat to insulation) arises due to internal loss within the machine. An important factor in

Continue Reading

What is Switching Station? | Working and Layout

What is a switching station? A switching station is a substation that does not contain power transformers and therefore does not change system voltage from one level to another. Switching stations usually operate at sub-transmission or transmission voltage levels. Depending

Continue Reading

Video: How Single Phase and Three Phase Transformer Works?

In today’s post, we will go through a video that explains the working of single phase and three phase transformers in detail.  We have already discussed the working principle of a transformer and Why Transformers are Rated in kVA, Not in kW? Watch the video below..   Open Delta (V-V) Connection of Transformers 29 Important Electrical Interview Questions you must Go through

Continue Reading

Transformer Bushing Types : RIP Bushing vs OIP Bushing

Transformer bushing types are categorized based on their material, manufacturing, and design mainly into the following types: OIP (Oil-Impregnated Paper) Bushing RIP (Resin Impregnated Paper) Bushing RIS (Resin Impregnated Synthetic) Bushing Resin Bonded Paper (RBP) Bushing Cast Epoxy Bushing You

Continue Reading

Three Phase Transformer Interconnections

The phase windings of three-phase transformers are interconnected to give a three-phase, three-or four-wire supply through three different modes of connection. They are mesh or delta connection star connection zigzag connection and each of these can be achieved in two ways.

Continue Reading

Substation Earthing System Design

We have already given an introduction to substation earthing system in an article published earlier. Today we are going to discuss the design of substation earthing system. Before 1960s the design criterion of substation earthing system was “low earth resistance.”

Continue Reading

Star-Star (Y-Y) Connection of Three Phase Transformers

There are different types of connection employed for three-phase transformers. The star-star (Y-Y) connection of three-phase transformers is the most economical type of connection for small current and high voltage transformers. The advantages and disadvantages of this connection are given below, Advantages

Continue Reading

Properties of Good Transformer Oil

Even though the basic functions of the oil used in transformers are heat conduction and electrical insulation, there are many other properties which make a particular oil eminently suitable. Properties of good transformer oil are explained in this article. Organic oils of vegetative

Continue Reading

Primary and Back-up Protection in Power System

Primary and Back-up Protection Primary protection (Main protection) is the essential protection provided for protecting an equivalent/machine or a part of the power system. As a precautionary measure, addition protection is generally provided and is called Backup Protection. In this

Continue Reading

Practical Transformer on No Load

Please read Ideal Transformer and Practical Transformer before continuing. Consider a practical transformer on no load i.e., secondary on open-circuit as shown in figure below. The primary will draw a small current I0 to supply  (i) the iron losses and  (ii) a

Continue Reading

Power Transformer and Distribution Transformer

The power transformer and distribution transformer are an important part of an electrical power distribution network. They are classified based on some of their characteristics. A power transformer is used in transmission network of higher voltages for step-up and step

Continue Reading

Open Delta (V-V) Connection of Transformers

Open Delta Connection is a method of transformer connection used to transform three-phase power using two single-phase transformers. In this article, you will learn how this connection is done and the theory behind this. The Scott connection is another method

Continue Reading

Low Voltage Switchgear

As per IEC 60947, switchgears with rated voltages up to 1000 V ac and 1500 V dc are termed as low voltage switchgear. The term ‘switchgear’ is a generic term encompassing a wide range of products like circuit breakers, switches, 

Continue Reading

Learn All About Rectifier Transformer

What is the Rectifier Transformer? Rectifier transformers are different from normal power and distribution transformers because they are special transformers made for industrial application. A Rectifier transformer is a special application transformer which includes diodes and thyristors in the same tank. 

Continue Reading