The integration of power-intensive producers and consumers into low voltage grids induces, but also requires, the transformation of these traditionally passive grids into active distribution grids. Different approaches for this evolution are possible. One popular option is the implementation of a smart grid platform. This platform operates apart form a conventional grid control system. It collects and processes real-time measurement data from the grid using automated functions. Subsequently, control commands are sent to actuators within the grid as necessary. However, these active low voltage grids are not yet standard. Therefore, a suitable test environment is required to evaluate and validate the platforms’ automated functions such as state estimation, congestion management and grid state assessment. To address this need, the paper presents an appropriate Power-Hardware-in-the-Loop (P-HiL) testbed for active low voltage grids and their corresponding platforms. Thereby, it starts with a systematisation of possible test cases. An example of a smart grid platform is provided to illustrate the necessary IT-components and their interaction with surrounding systems. Furthermore, the digital twin for the simulation of the real low voltage grid and the interdependency between hard- and software within the implemented testbed are explained.