# Communication Network Standards for Smart Grid Infrastructures
## 2 Network Standards That Support Communication in Smart Grid Infrastructures
### Distribution Automation  
The electricity distribution system in countries outside Europe includes distribution sub-stations which supply energy through long-distance lines (250 Km or more). As a result, in these systems voltage losses and power outages are very serious problems, which may lead to social problems and significant revenue losses for utilities [38]. To overcome these problems, over-the-air distribution lines are supported by Sectionalizers & Reclosers [39], which can be used to reshape power in the event of a disturbance. Furthermore, specialized equipment, such as voltage regulators, power regulators, and fault indicators, are utilized to ensure optimal operation and assist troubleshooting [27, 35].  
The introduction of microprocessor-based intelligent electronic devices (IEDs), together with cost-effective communication technologies, upgrades and automates the processes of energy distribution and rapid debugging and isolation of malicious material [40, 41, 42]. Therefore, based on the effective automation of the distribution process, utilities have the opportunity to create new business models of highly reliable power supply for both critical and industrial applications as well as residential consumers.  
Conversely, the structure of the power distribution network in Europe is based on a completely different approach. The backbone of this structure is a very dense grid of a large number of distribution substations while the energy transmission lines typically have a length of 5 to 20 km and the average number of served customers per single distribution feeder is usually less than 1000. Additionally, the connection of the loads to the grid is performed with precise programming and measurements, which lead to highly symmetrical loads. Furthermore, the distribution of substations are fully automated and include microprocessor, protection relays [43], actuators, etc., so that they can be remotely controlled in real time [1, 16, 32].  
Low-voltage transformer stations operate manually, as there is no incentive to automate distribution feeders because, in the event of disruptions, the number of affected customers is low, as is the amount of revenue loss. Nevertheless, the increasing integration of diffuse generation systems, such as low-voltage photovoltaic systems or medium-voltage wind turbines, creates voltage quality problems and makes it difficult or impossible to protect them with conventional non-automatic surge detectors [7, 24, 38].  
For the automation of the distribution systems, the remote control and the supervision of the secondary substations and transformers, is considered vital. Therefore, the exchange of information between them and the management system must be based on common operating protocols, which will provide, among other things, cybersecurity. This directly suggests that they must also support all communication technologies, given the different geographical conditions and infrastructures encountered. Furthermore, the implementation of protection systems should meet the individual specifications of distributed generation systems and, more generally, the automation of the European distribution system and consider the developments in the technological specifications of micro-networks [14, 23, 44].  
IEC 61850-7-4 covers a very large set of use cases for various types of distribution automation and supports the most prevalent information data models. Moreover, for the interconnection of distributed power sources and their remote monitoring, standardizations for the development of a crosslinking profile between IEC 61580-7-420 and IEC 61968, respectively, have been proposed. Finally, IEC 61970 provides a set of guidelines and techniques for active energy distribution and efficient operation of the energy management systems [34, 45, 46, 47].