Recently “Wide Area Monitoring, Protection and Control (WAMPC) systems” are proposed and used in power systems. PMU is the main component of WAMPC. Higher speed of PMU and synchronous measurement of voltage and current phase and amplitude are advantages of PMU compared with SCADA system. Hence, complete observability achievement of network state while minimizing of required PMUs is essential object of this paper. This requires complex difficult numerical optimization due to dispersed matrixes in large systems. This paper uses topological analysis method for solution of this type of complex nonlinear optimization problems. Genetic algorithm(GA) and Binary Integer Programing (BIP) are used in this paper for optimization. Double redundancy for sensitive substations observability is considered to emphasis their importance. A standard IEEE 14 buses and a real 30 buses Khouzestan network are used in comparative study.