# Telecommunication Technologies for Smart Grid Projects with Focus on Smart Metering Applications
## 4 Smart Metering Applications--Smart Grid Projects
### Remarks--Technological Trends on Telecommunication Technologies  
It can be concluded that there is a growing interest in the smart grid field, with an extended number of ongoing/realised projects. As it can be observed from our analysis presented in previous subsections, the telecommunication technologies listed in Section 2 are used for the smart grid projects' realization. Different technologies are used, depending on different objectives and goals of each project, different locations and different circumstances under which the technologies are tested. Smart metering plays an important role on the smart grid as a whole. All of the projects described are directly or indirectly linked to smart metering applications. It is noteworthy that 26 of them have among their immediate goals smart meters' installation and utilisation. In general, the concept of the two telecommunication links is followed, as explained in Section 1. In 21 of the analysed projects, explicit information is found about the telecommunication technologies used regarding smart meter data transmission. Power Line Communications and specifically NB-PLC are popular solutions for the first link of transmission, since 15 out of these 21 projects use smart meters based on this technology. Wireless solutions are used by eight out of these 21 projects for data transmission from the smart meter to the data concentrator, whereas in four of the projects it is explicitly mentioned that both NB-PLC and wireless technologies are used. One factor for such a selection can be the topology of the site. Among the wireless options for the first transmission link, ZigBee is a popular solution along with GSM/GPRS. Regarding the second link of transmission, wireless options are the dominant solutions for the aforementioned projects, with GSM, GPRS, 3G being popular technologies for this purpose, since in 12 of the 21 projects information about the usage of such technologies can be explicitly found. More sophisticated solutions, like UMTS and LTE are mentioned in one project, whereas PLC is also found in one project for the second transmission link. As an alternative to these 21 projects, smart meter data transmission to the utility center through the customer's internet link is realised in another project. Apart from smart metering data transmission, other telecommunication technologies are used for various purposes. In five of the projects analysed in the previous subsections, we can find information about in-home networks or communication networks within the building. The ZigBee protocol is utilized for such purposes in four out of these five projects, BB-PLC is chosen in two of them, whereas in one of them both BB-PLC and ZigBee are used. The HomePlug specification is mentioned in one of these projects (HomePlugGreenPhy) as well as the IEEE 802.11 protocol for communication issues within the building. The technologies used for sensor networks are explicitly mentioned in three of the projects examined in the previous subsections. ZigBee is the solution selected in two of these projects, whereas wireless connections are mentioned in another project. In one of these projects the usage of wired solutions is also mentioned along with ZigBee. Another topic for which information can be extracted is the data transmission on the MV network. In 3 of the examined projects, the technological solutions for data transmission through the MV network are mentioned. In all of these three projects, wireless solutions are chosen, like GSM, WiMAX and 3G. In one of them, BB-PLC technology is also used along with the wireless solutions. It should be noted that in this work the examined projects that consider research on the MV field are the ones that involve also smart meter applications. However, telecommunication technologies used in the MV smart grid is an important topic for investigation and several relevant papers can be found in the literature.