Passive distribution networks tend to become active, due to the high penetration of photovoltaic units, battery energy storage utilization and their combined active participation to distribution network operation. In this paper a framework for the assessment of the impact of PV and BES systems on voltage profiles and power losses of active distribution networks is proposed. Also, the utilization of the BES is evaluated. The proposed methodology is applied to statistically analyse results obtained from annual timeseries power flow calculations in a real 18-bus low-voltage network considering various operational scenarios; the obtained results are quantified using a set of probabilistic indices. The proposed framework can be a useful tool for system operators to identify operational challenges and ensure the optimal exploitation of network assets.