Traditional power systems were characterized by passive end-users, oriented mostly on power delivery. Also, power system operators planned the generation of large power plants so that it matches electricity demand. In recent years, the paradigm of planning and operation of power systems, and especially distribution systems have significantly changed.
The green energy transition and different climate packages emphasize the need for the reduction of greenhouse gas emissions and in general, the negative impact of power systems on the environment. In order to do so, the integration of renewable energy sources and other low carbon (LC) units becomes a vital part of the planning and operation of distribution networks. A recent increase in electricity prices and other energy sources, e.g., gas and oil, often used in heating and transport, combined with the decrease in prices of LC technologies, caused by technological development, encourages end-users to invest in photovoltaics (PVs), heat pumps, electric vehicles (EVs) and other LC units. Therefore, the share LC units in distribution networks, i.e., distributed energy resources, continuously grows.
Despite their positive environmental and financial impact, they create numerous technical issues for Distribution System Operators. Increased PV production leads to overvoltage and reverse power flows, while uncontrollable charging of EVs can cause network congestions and undervoltage problems. Integration of LC units is also related to different power quality problems. Since most of them are power electronics-interfaced to a network, combined with non-linear loads in a network, they increase the harmonic pollution in distribution networks. Even though end-users can be single-phase, or three-phase connected to a network, most of their devices are single-phase connected. Additionally, based on their maximum power, LC units can be single-phase connected. Single-phase connection only contributes to the increase of voltage and current unbalance. Deterioration of power quality leads to increased technical, and consequentially financial losses, a decrease in the equipment’s performance and their expected lifetime.
To enable further integration of LC units and to ease the operation of smart distribution networks, DSOs require specialized tools that will enable the assessment of LC units’ impact but also propose solutions that will help in resolving technical challenges. Recently, these solutions become more oriented toward the exploitation of the end-users potential. Distribution and especially low voltage (LV) networks are often characterized by low observability. Network topology and other data required for the analyses and simulations are often unknown, which only hinders the assessment and operation processes. Recently, the number of smart meters and related communication infrastructure installed in distribution networks has grown and