: Complex voltage at bus i;
: Difference between
and 
: Susceptance of SVC
: Objective function
: Total fuel cost of all the generators in $/hr
: Total real power losses in MW
: Net voltage deviation in p.u
: Total loading capacity of transmission lines in p.u
: Active Power transmission line losses, MW
: The svc reactive power in MVAR
: Bus voltage at ith bus, V
: Minimum voltage at bus i, V
: Maximum voltage at bus i, V
: Minimum real power generation, MW
: Maximum real power generation, MW
: Minimum reactive power generation, MVAR
: Maximum reactive power generation, MVAR
: Apparent power flow from bus i to j, MVA
: Active power flow from bus i to j, MW
: Reactive power flow from bus i to j, MVAR
: Admittance of the element between bus i and j
Z : the line impedance (p.u)
X : the line reactance (p.u)
Qj : the reactive power at bus j (receiving end bus)
Vi : the voltage magnitude at bus i (sending end bus)
FVSIij: FVSI for line connected between bus i and bus j (p.u)
PL : total active power losses (MW)
QL : total reactive power losses (MVAR)
PGi : the active power generation at bus i (MW)
PDi : the power demand at bus i (MW)
Sk : the apparent power in line k (MVA)
Skmax: the maximum apparent power in line k. (MVA)
Vk : the voltage magnitude at bus k, V
Vkref : the reference voltage magnitude at bus k, V
ntl :no. Of transmission lines
ng : no of generator buses
N : no. Of buses
α : random movement factor
β : attractiveness parameter
γ : absorption parameter