Why not 400KV to 11KV Step Down Transformer Directly Used in a Transmission System?

 

Fig- Typical Electricity Network System

The electricity network system mainly works under three major sects- Power Generation, Power Transmission, and Power Distribution.

Why can't we step down 400KV direct to 11KV in a transmission system?

To find the answer to why we cannot use the high-voltage or extra-high voltage step down directly to the distribution level voltage, let us know the transmission and distribution voltage level from the generation station to the user connection point.

Electricity Generation Voltage

Transformer Winding Resistance Test by DC Current

How Do You Do Transformer Winding Resistance Test by DC Current?

Considering the basic principle of operation is to inject a DC current through the transformer winding to be measured, and then read the voltage drop across that winding. 

We may refer to the formula for DC voltage across the transformer as, V = I * R  

where, 

V= DC voltage across transformer winding;

I = DC current through transformer winding; &

R = desired calculated resistance of the transformer winding.

Magnetic Leakage of a Transformer Breaks Ideal Characteristic

 Fig-1: Magnetic Leakage of Transformer  

How does magnetic flux determine the ideal transformer is not possible in practice?

Generally, it is assumed as our elementary knowledge about the transformer theory that the flux linked with the primary winding is also linked to the secondary winding.

Why Does Transformer Impedance Descrive in Percentage?

Fig-A Typical Transformer

Describe Why Does Transformer Impedance  Measured in Percentage

The rated impedance of a transformer is the voltage drop on full load because of the winding obstruction and spillage reactance communicated as a level of the evaluated voltage.

Buchholz Relay for Power Transformer Protection Device

How does a Buchholz Relay Protect Power Transformer?

A Buchholz relay is a protective device used to protect power transformers from internal faults and incipient failures. It is an essential component of a power transformer's protection and monitoring system. The Buchholz relay operates on the principle of detecting abnormal conditions within the transformer's oil-filled tank. Here's how it works and how it protects power transformers:

Transformer Equivalent Resistance

Fig-1: Transformer Equivalent Resistance

Fig-2: Transformer Equivalent Reactance

How to Calculate the Transformer Equivalent Resistance and Reactance?

CT (CURRENT TRANSFORMERS) IN ELECTRICAL DISTRIBUTION SYSTEM

What is CT or Current Transformer in an Electrical Distribution System

The CT an abbreviation of Current Transformer is a type of instrument transformer that is used to measure the current in AC or Alternating Current systems, taking the reduced amount from its secondary winding which is proportional to the primary winding that is being measured.

Wye-Delta or Star-Delta Connection Transformers

Why Transmission Line Transformers are used as  Star-Delta or Star-Wye connections? 

The main use of the star-delta or star-wye connection is at the substation end of the transmission line where the voltage is to be stepped down. 

The Efficiency of a Transformer

In our other article All-day Efficiency of Transformer, we have learned what is all-day efficiency and how to calculate it. In this article, we want to know the efficiency of a transformer and the calculation formula.

Fig: Transformer Efficiency Curve

What Exactly is Meant by Transformer Efficiency?

A transformer's ordinary or commercial efficiency is defined as the ratio of output power to input power.

Efficiency = η = Output / Input

Efficiency = η= Output / (Output + Losses) 

As Input = Output + Losses

How do you know if a transformer is step up or step down?

Fig: Step-up and Step-down Transformer Construction

What is meant by a step-up and step-down transformer?

We all are familiar with the Transformer and its different types and uses; we may have someone very expert and working with a transformer in our limited field or someone newer to the introduction level. The fact is that sometimes we face a few critical problems in our working field. Today we will discuss and share our knowledge about how we find the transformer is step-up or step-down when there is no identification marking.

Transformer Construction and Configuration

Who invented the transformer?

Electric transformers were invented by William Stanley in the United States in 1885, and it is also said that the transformer was invented by Michael Faraday in 1831 in Britain.

Definition of Transformer

If we look at the definition of Transformer above then we will find that it is a device that either step-up the voltage or step-down, that is, according to the corresponding decrease and increase of current.

The transformer is actually an electromagnetic energy conversion device. Or,


There is a device, in which the energy which is received is converted into primary winding first in magnetic energy and then it is reconverted again into secondary energy in electric energy.

Transformer configuration

Now let us know about the Transformer's Parts.

Although transformers have many parts but the most prominent of them are three parts,

1. Primary Winding of Transformer;
2. Transformer's Magnetic Core;
3. Secondary Winding of Transformer.

Primary winding

This is the primary winding that produces magnetic flux when it is connected to an electric source.

Transformer's Magnetic Core

The magnetic flux generated in this primary winding is passed through a low reluctance path which is linked to the secondary winding and it creates a closed magnetic circuit.

Secondary Winding of Transformer

The flux that occurs in the primary winding is passed through the core which is done with the secondary winding. This winding is also wrapped in the same core and it also produces the required output of the transformer.

The core of the transformer is used to provide a controlled path to the magnetic flux that is generated by the current in the transformer that is flowing through the windings, also called coils.

Transformer major parts

A Basic Transformer has four primary parts. Which consists of Input Connection, Output Connection, Windings or Coils and Core

Transformer Input Connection:

The input side of the transformer is also called the primary side because the main electrical power that is changed is connected to this point.

Transformer Output Connection:

The output side or secondary side of the transformer is the part where electrical power is sent to the load. Depending on the load requirement, incoming electric power is either increased or reduced.

Transformer Windings:

Transformers have two windings, one is primary winding and the other is the secondary winding.

The primary winding is the coil that draws power from the source.


The secondary winding is the coil that delivers energy to the load is transformed or changed voltage. Often these two coils are subdivided into many coils so that the creation of flux can be reduced.

Transformer Core:

The transformer core is used to provide a controlled path to the magnetic flux that is generated in the transformer.

This core is usually not a solid bar of steel, but rather a group of many thin laminated steel sheets or layers. It is designed because it can reduce or completely eliminate heating.


Transformers typically use one of the two cores described below:

Core Type and Shell Type:

These two types are different from each other in the way their primary and secondary coils are wrapped around the steel core.

Read more about Core Type and Shell Type Transformer in-

Core Type and Shell Type Transformer Basic and their application ranges.

Conversion of 2-Winding Transformer into Auto-transformer

Conversion of 2-Winding Transformer into Auto-Transformer

Any two-winding transformer can be converted into an auto-transformer either step-down or step-up. The figure below shows such a transformer with its polarity markings. Suppose it is a 20-kVA,

Three-phase Transformer Connections

Three-Phase Transformer Connection Procedure in Electrical Energy Transmission

The three-phase transformer consists of three transformers either separate or combined with one core. The primary and secondary of the transformer can be independently connected either in the star or delta. There are four possible connections for a 3-phase transformer bank.

Transformer Open Circuit and Short Circuit Test

Open Circuit Or No Load Test and Short Circuit Or Impedance Test On Transformer can carry out economically without loading a Transformer.

Open Circuit Test And Short Circuit Test on Transformer are performed to find the parameters of the equivalent circuit of the transformer and losses of the transformer. These two tests are conducted to determine the core loss, copper loss, and equivalent circuit parameters of a transformer.

The performance of a transformer can be calculated on the basis of a Transformer  Equivalent Circuit which contains four main parameters:

Why is an auxiliary Unit Transformer and a Station Transformer used?

What is the function of a station transformer and auxiliary transformer in a Power Plant and a Power Station?

If you work in a power plant or power grid station or are familiar with such kind of power generation or power transmission system, you must know the function of the station transformer or auxiliary transformer. I feel obliged to answer this question for those who are a little bit far from this kind of working field. 

Condition for Maximum Efficiency of Transformer

The ordinary or commercial efficiency of a transformer is defined as the ratio of output power to input power.

Efficiency = η = Output / Input

Efficiency = η= Output / (Output + Losses) 

As Input = Output + Losses.

Maximum Efficiency of Transformer

Ideally, the Maximum Efficiency of the Transformer is 100% considering no loss and zero voltage regulation. As there is no moving part in the transformer, there will be no frictional losses so it will be around 97–99%.

The efficiency will eventually go down for a number of reasons.

• Copper losses 
• Copper losses 
• Core and eddy current losses

Why Transformer Tap Changing is Required?

Fig-Transformer Tap Changers Line Diagram

What is the principle of Transformer Tap Changers?

We will try to understand the principle of a transformer tap changer and try to find the answer to the question- Can a transformer be tapped when it is on a load? Why is a tap changer used on an HV side?

TRANSFORMER OIL AND IT’S INSULATING PROPERTIES

What Is Transformer Oil?

Transformer oil actually is Insulating oil that has excellent stable electrical insulation properties at long-time high temperatures. Due to the mass use of this insulating oil in an electrical oil-filled transformer, commonly it is called transformer oil. Not only in transformers, but it also uses in high-voltage capacitors, oil circuit reclosers, high-voltage switches & circuit breakers, florescent lamp ballast, etc.

Transformer Oil or Insulating Oil also known as mineral insulating that is normally obtained by fractional distillation and subsequent treatment of crude petroleum.

The chemical name of oil used in transformer

Transformer Equivalent Circuit Diagram

How to draw the Equivalent Circuit Diagram of a Transformer?

If you want to draw the Transformer equivalent circuit, it would be like the below:

Fig: Equivalent Circuit Diagram of a Transformer.

What should be considered during drawing the Transformer equivalent circuit diagram?

Considering the two major parts of a transformer- primary winding and secondary winding with their parameters the equivalent circuit would be as above;

Wireless Electrical Energy Transmission

WEET, wireless electrical energy transmission is now an issue to transfer electrical power on large-scale and longer distances; because wireless energy transfer system is not a new question. Electrical energy transmission networking systems already use wireless energy transfer technology or unlike direct electrical connection. WEET system will be clear if you review your knowledge about the basic working principle of electrical transformers.

Now today’s target is to transfer electricity without wire from the source to the consumer’s end on a large scale. Already there are many demonstrations and operational stuff regarding wireless electricity transfer on a normal scale, like- mobile battery chargers, operating TV, laptops, etc. devices.

What Is the Wireless Electrical Energy Transmission Technology?

Engineers’ are searching for a practical technology to transmit electrical energy