Modern voltage regulation methods for network planning and operation in low voltage grids

Sustained integration of distributed renewable energy sources, especially photovoltaic generation in low voltage grids, has driven the need to expand grid capacities in recent years. Solutions to find economic justifiable approaches for mains operation in an aging grid environment have become indispensable. This paper highlights the design of a probabilistic simulation environment and several methods of voltage regulation using photovoltaic inverters and a controllable distribution transformer. Furthermore, it provides the possibility to rate these methods taking all conceivable grid states into account. Thereby the probabilistic simulation is based on actual, measured field data instead of standardized profiles. The aim is to create a simulation environment in which different grid situations can be simulated while the voltage levels are affected by different voltage regulation methods. The relative frequency of occurrence for the voltage levels shows - as a simulation result - the state of the grid, the voltage levels to be expected and their respective probabilities of occurrence. A comparison to reference grid simulations is attempting to generalize the functionality of controllers and drawn conclusions. This allows distribution system operators optimizing their grid planning by adding unconventional methods of influencing the voltage at lowest levels. Especially low voltage grid simulations with few grid participants and critical network states are lacking accuracy, when modeled by standardized profiles, will benefit from this probabilistic approach.