1. Background and progress required beyond the state of the art
Historically, power systems were organized as monopoles involved in the whole electricity value chain, i.e. from power generation to consumption. Electricity companies had the responsibility of long-term planning as well as operational planning for managing the power system, in connection with both the generation (the electricity was produced by large power plants) and consumption. Thus, these vertically integrated companies had a comprehensive vision of the system and were focussing on supplying their native consumers. Power installations, transmission and distribution networks were designed and sized to meet this objective.
Yet, in a global and open European electricity market, whereas producers act in a competitive environment, the grid has become a shared infrastructure acting as a facilitator for all stakeholders of the electricity market. This paradigm change  allows all producers who inject energy and all consumers who extract energy at different times to be connected, thereby increasing the global social welfare. The daily operation of such infrastructure is ensured in a regulated environment by system operators.
In this context, the role of DSOs is to guarantee the distribution network reliability, i.e. both maintaining the power quality at distribution level since the existing grid was initially designed for one-directional electricity flows only, and ensuring the security of supply at distribution level in order to deliver energy to each consumer within its own area of operation. This overarching goal is challenged by several issues that should be taken into account by all DSOs in a near future in order to keep a constant balancing between generation and consumption.
Firstly, many regulatory incentives in Europe have significantly impacted the development of dispersed generation installations. The emergence of environmentally small-scale generation units is mainly based on renewable energies such as wind turbines, photovoltaic panels, biothermal and geothermal generation. These distributed generation units are planned to be directly integrated into the network at LV and MV level as they are intended to be close to the final consumers. This renewable energy integration will represent a dramatic change in the electricity generation and distribution. To begin with, it challenges the operational planning at distribution level, particularly when considering the variability of renewable energy sources and/or their distributed nature: the interconnection location may not be adequate (e.g. wind power sources far from the consumption points can induce network losses or local constraints such as congestion in MV networks) and their generation may be not time-relevant (e.g. peak load at night not mitigated by relying on PV installations). To overcome this planning matter, the development of planning and forecasting tools at distribution level are required in order to model the Impact of DER on Distribution Networks.
Moreover, the integration of DER may also trigger interconnection problems. The centralized structure where power flows from the transmission system towards the distribution system (waterfall) is now being evolving as small DER units connected at low and medium voltage can impact the traditional power flow. As matter stands, if a distributed generation source injects a significant amount of energy within the distribution grid, a reversion of unidirectional flows may occur whereas the network was not originally designed for handling bi-directional flows. This integration of DER, besides the increase of the network hosting capacity, calls for an improvement in the network observability as well as a greater degree of controllability with regard to DERs, thereby requiring novel distribution network management tools.
Secondly, it is admitted that the distribution system was relatively less developed in terms of integration of state-of-the art measurement technologies and monitoring and control systems in comparison with the transmission system. This is due to the historical role of distribution networks, restricted to delivering energy in a descendant flow. The low voltage has so far been a “blind spot” for network owners. In the new context of the European electricity market, the missions and objectives of DSOs have evolved: the separation between transmission and distribution into distinct networks has provided DSOs with novel responsibilities as well as economical and technical constraints. The whole distribution network is thus moving towards developing new equipment, advanced grid automation and distribution network monitoring technologies in order to monitor normal and undesired situations. From the DSOs point of view, the monitoring of the low voltage network is of paramount importance regarding load-flow optimization at local level, faults detection, power quality and optimization of maintenance operations. The modernization of the distribution grid is an ongoing process that currently requires further development concerning new management methodologies and control methods (i.e. new algorithms to optimize system topology) as well as new technologies that improve the distribution system measurements (e.g. smart meters).
Moreover, the increased cooperation between TSOs and DSOs may lead TSOs to require in-depth monitoring of distribution network in view of using islanded mode of operation and safe reconnection.
The massive roll out of smart metering carried out by EU members will result in a dramatic increase in data to be acquired by Supervisory Control And Data Acquisition (SCADA) systems. The monitoring, control and data acquisition will not only deal with distribution network components and cooperation between system operators, but will also involve consumers throughout Advanced Metering Infrastructure (AMI) . AMI is indeed known as the ensemble of technologies used to gather and analyse the electricity consumption data necessary to make demand response possible. AMI encompasses measurement devices, collection systems and communication networks. It covers consumption data gathering, data transmission and data reception. Integration, interfaces, standards, and open systems will therefore become a necessity . However, it is assumed that consumer acceptance will be low if such a system is not capable of protecting their private data or is not able to provide reliable and trustable information regarding price signals and/or commands directly received at their home smart meter. Thus, both consumer-to-provider and provider-to-consumer communication links in AMI raise security and privacy concerns . As far as the security of consumption data is concerned, data protection tools and cyber security issues shall be addressed.
2.Outcomes provided by the projects that address the challenges of the cluster
Grid4EU is the biggest smart grid project to be funded by the European Union, financed to the tune of €25 M by the European Commission, and costing €54 M overall. The project is led by six European DSOs covering more than 50% of the electricity supply in Europe. The project consists of six demonstrators (one per DSO leading the project), which will be tested over a period of four years.
New methods for operational planning at distribution level and active operation of low voltage networks can reduce the high costs associated with upgrading power distribution infrastructure to host the expected additional generation and load. DG Demonet Smart LV grid addresses this challenge and focuses on making available new network management possibilities while taking into account the deployment of advanced meter reading systems in many places. The main objective of the project is to find an efficient way for integrating distributed generation from renewable energy (PV) and electro mobility with regard to optimized investment of the existing asset base in low voltage grids. The focus is to increase the hosting capacity for distributed energy resources (DER) and e-mobility of low voltage distribution networks.
C. DG Demonet MV grids
Within DG DemoNet MV grids, voltage control concepts were developed in numerical simulation environments and based on real network data (three case studies typical of Austrian medium voltage networks). Moreover, both the economic and technical efficiency have been evaluated and compared to a reference scenario. As a result, two different solutions for voltage control in MV networks have been validated and successfully demonstrated: coordinated voltage control and distributed voltage control.
The goal of the KIC-ASS project (Knowledge and Innovation Community – Active Sub Stations) is to bring research institutes and industry together to develop key cost efficient components for future smart secondary substations, thus contributing to improved distribution network operation through better distribution network monitoring technologies. Within KIC-ASS, the hardware components that enable measurement in, and control of the Active Distribution Substation, as well as initial algorithms for data analysis, are developed. The focus of the KIC-ASS project is to develop components that can be installed within an MV/LV substation from an economic perspective as well as from a technical perspective.
The basis of the overall concept of DISCERN is to utilise the experience of major European DSOs with innovative and efficient distribution network monitoring technologies . The complementary nature of the demonstration sites with regard to the specific challenges as well as technological and operational solutions serve as the main resource of DISCERN.
Meter-ON is a coordination and support action to steer the implementation of smart metering solutions throughout Europe. The project aims at speeding up and optimizing the adoption of smart metering technologies and infrastructures in Europe by effectively collecting the most successful experiences in the field and highlighting the conditions that enabled their development.
 Electrical Distribution Networks. Nouredine Hadjsaïd, Jean-Claude Sabonnadière. John Wiley & Sons. January 2013.
 Smart Grids. Infrastructure, technology and solutions. Stuart Borlase. CRC press, 2013.
 Distributed Sensor Networks, Second Edition: sensor networking and applications. S. Sitharama Iyengar, Richard R. Brooks. CRC Press, 2012.