This paper presents the use of a modular time domain model to study the interaction of single-phase photovoltaic inverters in public low voltage networks. Currently, specific time domain implementations of individual inverters are designed and studied from a power electronics perspective. If circuit and controller are unknown, e.g. for commercially available photovoltaic inverters, time domain modelling is not possible and measurement-based black-box models in frequency domain have to be used. This paper proposes a modular modelling approach for generating a large and realistic set of different inverter implementations for general and probabilistic system-level studies of their interaction in public low voltage networks. The modular model can be used for time domain studies but also enables to derive frequency domain models as required in case of large-scale studies. It is shown in frequency domain that the modular model represents adequately commercially available devices, which have been characterized by black-box measurements in the laboratory.