Voltage stability has become an important issue in
planning and operation of many power systems. This work includes multi-objective
evolutionary algorithm techniques such as Genetic Algorithm (GA) and
Non-dominated Sorting Genetic Algorithm II (NSGA II) approach for solving
Voltage Stability Constrained-Optimal Power Flow (VSC-OPF). Base case
generator power output, voltage magnitude of generator buses are taken as the
control variables and maximum L-index of load buses is used to specify the
voltage stability level of the system. Multi-Objective OPF, formulated as a multi-objective
mixed integer nonlinear optimization problem, minimizes fuel cost and minimizes
emission of gases, as well as improvement of voltage profile in the system.
NSGA-II based OPF-case 1-Two objective-Min Fuel cost and Voltage stability
index; case 2-Three objective-Min Fuel cost, Min Emission cost and Voltage
stability index. The above method is tested on standard IEEE 30-bus test system
and simulation results are done for base case and the two severe contingency
cases and also on loaded conditions.