Tenth lecture about Power system protection

In this lecture will educate the sychronism and Relays  :

The Synchronism : 

Founded generation units in all over the country to make the connection between the 

units and run in the synchronous and reduce due to increase the loads .

in case of out the heavy loads , the generator speed increase and may be explodes .

Type of Relay :

Definite Relay :

Determine the current value and the value of delay time .

Inverse Relay :

• Inverse .
• Very inverse .
• Extremely inverse .

Inverse Relay :

 

• Family of curves .
• For Transmission line protection .
• T = 0.14  * TDS / (m^0.02) -1 .

Very Inverse :

• Family of curves .
• For Ring feeder protection .
• T = 13.5 * TDS / m -1 .

Extremely Inverse :

• Family of curves .
• For cable - transformer .
• T = 80 * TDS / ( m^2 ) - 1 .

In this shape  , it's showing the difference between the 3 type of it :

Inverse Definite minimum Time (IDMT) :

 the part  one :

When the current increase in the part one the time  inverse proportional with the 

currrent .

in the part two :

 in case of occur fault , disconnect immediately . 

To continue our course of Power Protection System :

[ The Eleventh lecture of Power System Protection ]

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