The hosting capacity of low-voltage (LV) networks is influenced by existing consumption and production in adjacent LV networks under the same medium-voltage (MV) network. Since LV transformers typically lack automatic on-load tap changers, both voltage and current limits require a joint assessment covering the MV network and all underlying LV networks. This paper introduces a methodology to include different MV operating conditions, like reserve operating paths, in the calculation of the hosting capacity for new production at LV networks. The MV voltage profile before the connection of new production, called the background voltage, is modelled to enable such analysis. The methodology is applied to an existing MV/LV network. The hosting capacity was lower, for the studied reserve operating paths, and the limitation was due to overvoltage issues. The proposed methodology is a valuable tool for distribution network planning. It was also shown that it is essential to use an accurate model of the background voltage for hosting capacity calculation of distribution networks.

The term “hosting capacity”, in the context of power systems, was first introduced in March 2004 and has since resulted in a range of applications and research. Network operators commonly use the concept to quantify the ability of their networks to accept new production and consumption. Academic research on hosting capacity took off seriously after 2010 and has resulted in thousands of publications. This paper presents a brief history of the early years of hosting capacity studies, gives an overview of the status of both applications and research, summarises the different methods and types of studies, and correlates all that with the underlying fundamental principles of the hosting capacity concept, as it was introduced in 2004. The main focus of this paper is to review and relate these methods and studies to the fundamental principles. Having a clear understanding of these fundamental principles enables a wide range of applications for hosting capacity studies with detailed methods and models. However, it also requires transparency to ensure a coherent analysis, correct interpretation of the results, and an open discussion between stakeholders. With research on hosting capacity, it is important to refer to the fundamental principles; with applications, it is important to maintain transparency and objectivity. 

This paper presents an approach to estimate the hosting capacity for distribution networks considering the impact of PV penetration at different voltage levels. The estimation and the method were selected such that the results were most suitable for distribution system planning. A time-series based method was used as it covers significant aspects needed for prioritising network reinforcement. The MV background voltage was modelled varying in time, assuming the same penetration level in the other LV networks supplied by the same MV system. The hosting capacity is defined as the maximum acceptable PV size per customer for a given PV penetration. Based on the different possible combinations of PV location, the probability of overvoltage and overloading is used as a performance index. The planning risk is used as a limit for the performance criterion. The method can be automated for a large number of networks due to using an IEC 61970-based input format. It also enables linking DSO network models to customer smart metre databases. The severity and risks of limit violations are analysed with different metrics from the time-series simulations. The change in background voltage with increasing penetration is shown to impact the results significantly. When considering it, the estimated hosting capacity was reduced by 32 %, on average.

About 15 000-customers are connected to the individual secondary distribution networks supplied through 48-medium voltage 10 kV radial feeders. The hosting capacity assessment uses the end-customer voltage magnitude rise and transformer thermal overload. The hosting capacity is estimated by applying the “stochastic mixed aleatory-epistemic method” to determine the voltage magnitude rise and load flow with solar PV. The minimum power consumption is compared with the solar PV power infeed through the individual transformers. The hosting capacity estimation is done for three-phase connected solar PV sizes from 3 to 18 kW. At moderate PV penetration (25%–50%), the results showed that overvoltage would limit the hosting capacity more often than overload, but it becomes an issue only for LV networks studied with more than 8-customers. Considering all LV networks, most of the customers could install 6 kWp. Even when installing PV systems of 18 kWp (about twice the average size today and about the maximum area of a typical residential roof), two-thirds of houses would not need an upgrade to withstand SS-EN 50160 voltage limits. The latter customers can connect solar PV units with 18 kWp size without overvoltage or overload issues.