what is the the zero , positve and negative sequence protection?

[emadshaaban]

hi all,
i have face this protection units (zero ,postive ,negative sequence )in protection relay (IMM9000 from CEE).so i didn't get the diffrent btewwen zero squeance and earth foult,positve squ- and short and negative squ- and unbalance ?and if thay are the same why thay call it by zero,positve& negative squenace?
thanks for help

 

[ScottyUK]

Google "symmetrical components" and study the theory. That should answer most of your questions.


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