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.
Three-Phase Transformer – Basics and Connection Methods
Open Delta (V-V) Connection of Transformers
What is Switching Station? | Working and Layout
How to Test Percentage Impedance of Transformer?
Transformer Bushing Types : RIP Bushing vs OIP Bushing
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
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
Why Transformer does not work on DC supply?
Did you ever think about what will happen to a transformer on dc supply? In this article, you will learn why the transformer does not work on the DC supply. You already know that dc supply cannot be used for
Why Current Transformer (CT) Seconday Should not be Open ?
Amazed why secondary of current transformer should not be open? If it is left open it may destroy the current transformer. So it is very important that the secondary of Current Transformer should not be kept open. The reason is quite
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
What are Protective Relays? | Types and Working
What is a Protective Relay? The protective relay was invented more than 160 years ago. During the last 60 years, it has undergone considerable change, the most obvious of which is its reduction in size. A protective relay is a
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
Transformer Oil Testing : Video Training
Transformer oil testing is just like a blood test in the human body. A blood test provides a doctor with a wealth of information about the health of a patient. A sample of transformer oil, taken correctly, can tell service
Transformer Oil Filtration and Hot Oil Circulation Process
Transformer Oil Filtration Plant is a self-contained unit to upgrade the quantity of oil. The duty cycle begins from pumping the dirty oil from the equipment (or container) to a heat chamber. After heating the oil to a predetermined
Transformer Oil – Tests and Purification Methods
What is Transformer Oil? Transformer oil is mineral insulating oil derived from crude petroleum. It is a mixture of various hydrocarbons. It consists partly aliphatic compounds (open chain compounds) with the general formula CnH2n+2 and CnH2n. Many oils also contain certain
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
Three-Phase Transformer – Basics and Connection Methods
Three-phase transformers are used in three-phase circuits to step up and step down the voltage according to the needs in a power system. You know that electric power is generated and transmitted using a three-phase system. The three-phase system has
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.
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.”
Substation Earthing System ( Grounding System ) – Earthing Mat
The substation earthing system comprises of a grid (earth mat) formed by a horizontal buried conductors. Read about design of substation earthing system here. The grounding system in substation is very important. The functions of grounding systems or earth mat in
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
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
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
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
Power Transformer Testing Methods – Type, Routine & Special Tests
An electrical power transformer has to go through a number of transformer testing procedures for confirming its specifications and performances. In this article, you will learn different types of transformer testing methods, test setup, and their acceptance criteria. Type of
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
Percentage Impedance of Transformer and Its Calculation
What is the Percentage Impedance? The percentage impedance of a transformer is marked on most nameplates – but what is it and what does the Z% figure mean? The impedance of a transformer is the total opposition offered to alternating
Parallel Operation of Single Phase Transformers
By parallel operation of single-phase transformers, we mean two or more transformers are connected to the same supply bus bars on the primary side and to a common bus bar/load on the secondary side. Such a requirement is frequently encountered in practice.
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
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,
Load Forecasting – Purpose, Classification and Procedure
What is Load Forecasting? Electrical energy cannot currently be stored in large amounts. It has to be generated whenever there is a demand for it. It is, therefore, imperative for the electric power utilities that the load on their systems
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.
Introduction to Gas Insulated Substations / Switchgears (GIS)
Gas-insulated substations (GIS) have been used in power systems over the last three decades because of their high reliability, easy maintenance, small ground space requirement, etc. This article is an introduction to Gas-insulated Substations. Gas Insulated Substation (GIS) also called
Insulation Resistance Test (IR Test) or Megger Test
Insulation Resistance or IR Test is carried out by maintenance engineers to ensure the healthiness of the overall insulation system of electrical equipment. It reflects the presence or absence of harmful contamination, dirt, moisture, and gross degradation. IR value will
Ideal Transformer and Practical Transformer
Ideal Transformer An ideal transformer is one that has no winding resistance no leakage flux i.e., the same flux links both the windings no iron losses (i.e., eddy current and hysteresis losses) in the core Although an ideal transformer cannot