Probabilistic capacity assessment for three-phase low-voltage distribution networks

The increase of photovoltaic panels and electric vehicles in low-voltage distribution systems leads to over-voltage, under-voltage, and congestion issues. These issues, related to new installations, add a considerable cost to distribution system operators, and therefore to customers. Distribution system operators want to limit these costs by determining the impact of photovoltaic panel production and electrical vehicle charging. This paper presents a probabilistic method enabling operators to evaluate the network capacity, defined as the number of new installations that can be added to the network without adapting it to overcome under- and over-voltage. The method provides multiple probabilistic performance indicators reflecting a large number of possible configurations resulting from new installations added to the low-voltage network. The evaluation of this method is done using a case study based on an existing European network. The method provides tangible results as the maximum number of photovoltaic installations or electric vehicle chargers within a defined confidence level. Results, in the test case, show that the capacity of the network is evaluated as a 45% penetration rate for photovoltaic installations, or 4% for electric vehicle chargers, with a 5% violation of operational indicators.