Why star connection does not get short circuited ?

   

  Hello guys, today we are going to discuss about an interesting question. Why star connection does not get short circuited ?

    Before the discussion , lets see what is short circuit and what is the cause of sc in a electrical system.

Definition: 

A short circuit is an abnormal condition in an electrical circuit where the electrical current flows through shorter pathway instead of following the circuit. 

Let's discuss in a simple way . 

Consider one phase and one neutral ,

Case I : connect them via a load ( it may be resistive, capacitive or inductive) 

 circuit will work under normal condition and the electrical energy passing though the resistor will be liberated in the form of heat in case of bulb without any short circuit .

Case II : connect them ( P and N ) without any load .

 Short circuit will happen

  From this , We understand that if phase and neutral are directly connected without any resistance or impedance between them, short circuit occurs.

Same thing will happen about 2 different phases ( for example , R and Y phase ).  

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Current rating in transmission line

Current rating in transmission line - how many ampere in transmission line

Today's topic of our blog is how many ampere in transmission line? It means that how many ampere current flows in the transmission line? 

Inshort answer :

The average current of our transmission line is around 700-800 A. In the distribution lines current is less than 100 A.  

How to predict the current rating in transmission line :

 We mostly use acsr conductor in our transmission line. We also have many types of this acsr conductor.

 Like dog is acsr conductor, panther acsr, zebra acsr and moose is acsr conductor. 

Now how much is in the transmission line Current flow will be, it depends on which conductor is used in the transmission line.

We use our dog acsr conductor on 33kV to 66kV voltage. If we talk about its current rating, then we use this conductor up to 300 A current. 

Just like that 

Panther :     66kV -132kV           480A 

Zebra :        220kV                     735A 

Moose:       220 kV- 400kV       800 A 

This is a method by which we can find out the current rating of the transmission line. There are 7 steel wires in all these conductors. We can differentiate these conductors by their number of aluminum conductors.  There are types of acsr with number of aluminum wires. 

Dog                 6

Panther           30 

Zebra              54 

Moose             54 

The number of aluminum conductors is the same in our zebra and moose conductor. 

But the thickness of aluminum conductor in moose conductor is more than that of zebra conductor, so it can conduct more current.

Table: 

                 Current         No. Of  Aluminium                      Rating           conductors

Dog           300 A          6

Panther     480 A          30

Zebra        735 A          54

Moose      800 A          54

Hope this helps you. Thank you ❤️

Why transmission line cables are loose ?

 

Why transmission line cables are loose ?

       Often when we look at the transmission lines going off the road, then we see all the lines slightly tilted. Also you can see in picture , there is a curve which is formed by transmission line due to losseness .

   After all, why are these lines kept loose? 

Before knowing the reason, we see some terms.

(01). The distance between two consecutive towers of an Overhead line is called span. 

(02)  Sag is the distance between straight conductor (which should be kept) and losse conductor (which is kept). The more tight the wire, the less the sag is. 

       

Inshort the Reason is  :  

       When this cable is loose, this cable allows vibration. Along with this, it also gives us protection from mechanical shocks that can come in our transmission.

     

Let's see how :

         You will know that our conductor, it expands when it is heated. It will expand and get bigger. Because if we heat a substance, then the millions of atoms in the subtance, they get energy in the form of kinatic energy. 

  Due to this, these atoms start to vibrate faster and the space between these atoms increases.

(1). Heat is generated due to the current flow in the conductor of our transmission line.

(2).On the other hand, according to the weather, heat is generated in it. Heat is generated in the transmission line due to the sun (like our metallic gate gets heated due to the sun.)

     

  Because of this, the amount of sag in the transmission line increases. But when the sun's ray is not there, then the value of the sag of the transmission line automatically decreases at that time.

    If we keep the transmission line tight, then heat will be generated in it, due to which there will be vibrations of atoms. And due to this mechanical shock on transmission line will be there to cut the transmission line by generating mechanical stress on it . That's why our transmission line is kept loose. 

Hope this helps you . Thank you ️❤️

why a bulb is called 0 watt?

 

Why a bulb is called 0 watt?

We all call a bulb as 0 watt bulb. But do you know why it is called 0 watt bulb? 

                       ---------   Zero watt bulb

Actually, no electrical equipment will do a work on 0 watt. To do work it will take electricity in either some points. 

Then why is it called 0 watt after all?

The reason for this is that the electrical meter we had till a few years ago was an analogue meter. And the analogue meter cannot read some watts.

 If that zero watt bulb is actually a 7 watt bulb, then people could not see anything rising on the meter. So this misconception had formed in the minds of the people that this is a 0 watt bulb.

And that's where this 0 watt bulb started. And this term became very popular in India.

Hope this helps you . Thank you ❤️.