Phasor Measurement Units (PMU) are essential parts of smart grids. There are several algorithms to determine the placement of these units for optimal observability of the system. In this paper two different hybrid methods and Integer Linear Programming method have been used for the placement of PMUs in the power system of Afghanistan. One of the hybrid approaches presented here is based on the combination of the Greedy and Breadth First Search algorithms. The other one is based on the Binary Search and Global Search algorithms. The power system of Afghanistan has been slightly modified to include the renewable energy sources. Results obtained have been compared between each other. The result of these algorithms are more proper than other algorithms like Depth First Search, Genetic Algorithm, Partial Swarm Algorithm and Binary Search algorithms that have been compared by other authors on IEEE test systems.