While many visualization techniques have been developed in recent years, few have been applied to power grid visualization. With the ongoing emergence of smart and distributed grids, it becomes increasingly important to improve and modernize legacy infrastructure. Visualization and simulation of power grids under real-life scenarios can help with and sometimes even discover new approaches and techniques that significantly improve and simplify network analysis, maintenance, and planning. This enables operators to spot key issues which are hard to detect otherwise. Creating visualizations for these problems is challenging as no obvious or trivial solutions exist, and many of them are associated with multi-dimensional data. This paper aims to provide a comprehensive overview of the methods developed for the visualization of power grids while evaluating the advantages and disadvantages of the single approaches. An outlook discusses open research questions and possible further improvements to the field.