Over the last decade, there has been a considerable increase in deploying phasor measurement units (PMUs) in wide-area monitoring, protection, and control of power systems, as well as the development of smart transmission and distribution grid applications. This chapter is focused on the demonstration of capabilities of DIgSILENT PowerFactory software for solving the problem of optimal PMU placement in power networks. The optimal placement has been viewed from the perspective of satisfying the observability requirement of power system state estimator. Optimal placement of PMU is formulated as a practical design task, considering some technical challenges like complete network observability, enough redundancy, and the concept of zero injection buses under PMU and tie-line critical contingencies. Furthermore, the meta-heuristic techniques on the basis of evolutionary computations are programmed as an optimisation toolbox in DIgSILENT Programming Language (DPL). A distinctive characteristic of the presented module is that the evolutionary algorithm is only coded in DPL without using the time-consuming process of interlinking DIgSILENT PowerFactory with another software package like MATLAB. In summary, the bus adjacency relationship matrix, zero injection bus (ZIB), observability in the presence of ZIB, and PMU/line contingencies are programmed in different DPLs and combined together with the DPL of an evolutionary algorithm to create the optimal PMU placement module. Also, the proposed toolbox is not case-dependent and can be run with the user-defined test systems, what is contributing to the proposed tool flexibility. Finally, the applicability and efficiency of the proposed optimal PMU placement module are investigated on the DIgSILENT PowerFactory version of IEEE 14- and 39-bus test systems.