The automotive PowerNet is in the middle of a major transformation. The main drivers are steadily increasing power demand, availability requirements, and complexity and cost. These factors result in a wide variety of possible future PowerNet topologies. The increasing power demand is, among other factors, caused by the progressive electrification of formerly mechanical components and a constantly increasing number of comfort and safety loads. This leads to a steady increase in installed electrical power. X-by-wire systems1 and autonomous driving functions result in higher availability requirements. As a result, the power supply of all safety-critical loads must always be kept sufficiently stable. To reduce costs and increase reliability, the car manufacturers aim to reduce the complexity of the PowerNet system, including the wiring harness and the controller network. The wiring harness e.g., is currently one of the most expensive parts of modern cars. These challenges are met with a wide variety of concepts. To fulfill the increasing power requirements, higher voltage levels can be introduced. Availability requirements can be met with redundant subnets. The complexity of the wiring harness can be reduced by employing a zonal architecture. The changes coming with the chosen topology will have a major impact on the components used in the low-voltage PowerNet and their requirements. In some cases, entirely new components will be necessary. For carmakers and suppliers, it is crucial to understand the different topologies and their implications to develop appropriate and safe components in the future. System simulations are an important tool to support these efforts. Due to the high variance of the discussed topologies and the considerable effort for building the models, we propose the implementation of a simulation toolbox featuring an automized model built-up. Here, the description and modeling of the PowerNet is based on a modular approach, which enables a rapid and efficient model built-up and simulation. This toolbox allows for a fast evaluation and quantitative comparison of different topologies.