\[CC_i=(lmp_{i1}-lmp_{i2})P_{li1,i2}\ \ \ \ \ \ \ \ \ \ i=1,2,\dots,N_i\ \ \left(7\right)\]
In which \(CC_i\) is density cost in line in ($/h) , \(lmp_i\) is LMP in \(i_2\) base in ($/MWh) , \(P_{lti}\)is the sent power from \(i_1\) base to \(i_2\) through line \(i\) and \(N_i\) is the number of lines of transmission network \cite{Foroud_2010}.