The eighth lecture about power system protection

to complete our course about our protection system  :

C.T Objective :

• Reduce the heavy current to suitable value : 5A -1A .
  
  
• Isolate the relay circuit from the primary circuit .

Requirement of C.T is achieve the accuracy in each :

• Current normal range .
• Several value of primary current .

Type of core of the current transformer :

1- Nickel - Iron .

2- Cold - Rolled silicon steal .

3- Hot - Rolled silicon steal .

Nickel - Iron :

• Low saturation level .
• High error .
• Good accuracy up to 5 - limit IR .
• Used with the instrument .

Cold - Rolled silicon steal :

• High saturation level .
• Low error .
• Good accuracy up to 15 - limit IR .
• Used with the protection .

Hot - Rolled silicon steal :

don't use in Measurement or protection .

Let's know : what the meaning of saturation :

 

 

 

Any equipment have iron core , in case of fixed the frequency  the voltage 

proportional to the flux and whenever the voltage increase , the flux increase until 

the iron core saturated by flux the the flux transmit to the winding and destroy it and 

it's know (Knee point)  ( K ) .

To continue our course of Power Protection System :

[ The Ninth lecture of Power System Protection ]

you can follow us by our page in the facebook click in it:

[ World Of Engineering ]