Internet of Things Application to Smart Grid

Transcription

1 Internet of Things Application to Smart Grid 1 Introduction Hamraz, Seyed Hamid December 2013 Computer Science Department, University of Kentucky Hamid.hamraz@uky.edu The Internet of Things (IoT) is a paradigm that is rapidly gaining ground within the facility the modern telecommunication technologies provide [1]. The basic idea of this concept is the pervasive presence around us of a variety of things or objects such as Radio-Frequency Identification (RFID) tags, sensors, actuators, mobile phones, etc. which, through unique addressing schemes, are able to interact with each other and cooperate with their neighbors to reach common goals. Unquestionably, the main strength of the IoT idea is the high impact it will have on several aspects of everyday-life and behavior of potential users. One of such applications IoT can provide is enabling the smart power grid. The smart grid is itself a paradigm, where the advanced telecommunication technologies are incorporated to the current electric power grid, thereby enabling real-time monitoring and control in order to reach more efficient electricity generation/consumption. In order to realize the smart grid two general approaches are identified: Utilize the networking capacity provided by IoT to have a sub-network between the power grid entities Utilize the communication ideas brought about by the internet or IoT to build the communicating grid Although the two approaches seem to be different, they are toward the same goal. In fact, both approaches should be utilized to efficiently construct little local networks, and develop them into the bigger networks with the aid of gateway technologies - depending on the requirements and the possibilities. For instance, at some point we may need to extend an extra cable to relay only the traffic of the power grid communications because the local internet infrastructure might have already been saturated. Trivially, whether to look to the smart grid as a subset of IoT, or as a similar and smaller network, the design and deployment of both are highly interconnected and share many common features. The problem the current paper is intended to address is how to optimally develop IoT/smart grid. Following this, section 2 provides how the IoT paradigm can be approached. Enabling technologies and design concerns are covered in section 3. Applications of IoT, especially with respect to the smart grid, are pointed out in section 4, and finally section 5 concludes the paper (Since the focus of discussion is bent toward the smart grid, specific issues of smart grid are interjected when needed). 2 Internet of Things: one Paradigm, many Visions Although the idea behind IoT is very simple, how to realize the idea, as well as the implications of that are quite complicated. This is due to the fact that different interested groups, such as stakeholders, business alliances, and research and standardization bodies, have been approaching the paradigm from different perspectives based on their specific background and finalities [1]. IoT can be approached from two trivial perspectives, things-oriented where the objects need to be augmented to build the networks -

2 and network-oriented where the current internet infrastructure should be extended to be able to include objects as well. Semantic-oriented approach is another perspective that will be implied as the IoT will come closer to reality, i.e., how to deal and exploit IoT considering its huge magnitude. Fig. 1 shows the three perspectives and their relationships. Fig. 1. The three perspectives to the IoT paradigm [1] As an example of the things oriented perspective, RFID tags are considered as the things to be networked, and form the IoT. In this perspective, objects need to be augmented to be smart in order to cooperate and form a network. As an example of design and architectural principles for smart objects, the authors in [2] introduce a hierarchy of architectures with increasing levels of real-world awareness and interactivity. In fact, such a hierarchical abstraction is necessary in the realization of the IoT/smart grid because of the very different capacities and needs of the participating objects and entities. In [3], collaboration among heterogeneous participating entities in the power grid is pointed out as the key feature in the realization of the smart grid. Having collaborating heterogeneous devices requires augmenting each device with a network capability, as well as an object abstraction layer to bypass heterogeneity. Within the internet oriented perspective, the internet is envisioned to be extended and encompass the objects. The IoT vision of the IPSO (IP for Smart Objects) Alliance [4] indicates that the IP stack is a light protocol that already connects a huge amount of communicating devices and runs on tiny and battery operated embedded devices. This guarantees that IP has all the qualities to make IoT a reality. Through a wise IP adaptation and by incorporating IEEE into the IP architecture, with the aid of 6LoWPAN [5], the full deployment of the IoT paradigm will be automatically enabled. Internet Ø [6] follows a similar approach of reducing the complexity of the IP stack to achieve a protocol designed to route IP over anything. According to both the IPSO and Internet Ø approaches, the IoT will be deployed by means of a sort of simplification of the current IP to adapt it to any object and make those objects addressable and reachable from any location.

3 Another non-trivial perspective from which IoT can be approached is the semantic-oriented perspective. Whether looking to the IoT paradigm from the things-oriented or net-oriented, IoT, when realized, is a huge network of enormous amount of objects. Therefore, issues related to how to represent, store, interconnect, search, and organize information generated by the IoT will become very complicated. Tackling this, semantic technologies can be utilized to appropriately model solutions for things description, reasoning over data generated by IoT, semantic execution environments and architectures that accommodate IoT requirements and scalable storing and communication infrastructure [7]. 3 Enabling Technologies for IoT and the Smart Grid In this section, we mention a few technologies that suffice to start off development of the IoT and/or the smart grid. 3.1 Physical Layer The physical layer within IoT will have the responsibility to uniquely identify objects, sense the environment, and inter-connect the objects to enable communication. One solution for this is the RFID systems [8]. Within the system, several RFID tags exist that can be read and interconnected by one or more RFID readers. RFID readers can serve as gateways to connect the local RFID network to other networks, such as internet, thereby interconnecting the world of objects to the digital world. RFID tags are generally powered passively through the query signal emitted by the reader. That makes them to have unlimited lifetime, and be very little in size considering the fact that they don t require to be accompanied by batteries. On the other hand, Sensor networks will also play a crucial role in the IoT. Within the sensor networks, the sinks node can serve as the gateway. In fact, this enables interconnectivity and cooperation with RFID systems to better track the status of things, i.e., their location, temperature, movements, etc. As such, they can augment the awareness of a certain environment and, thus, act as a further bridge between physical and digital world. Sensor networks are generally run over a wireless medium; they are usually referred to as Wireless Sensor Networks (WSN), and route toward the gateway in a multi-hop fashion. There are battery-operated, and the lifetime is therefore limited. Furthermore, integration of RFID devices to the sensing ones yield new applications for IoT, where an RFID and one or more sensors are integrated to one device serving both as a uniquely identifiable object and a sensing device. Several solutions have been proposed in this direction. As an example, the WISP project is being carried out at Intel Labs to develop wireless identification and sensing platforms (WISP) [9]. WISPs are read by standard RFID readers, harvesting the power from the reader s querying signal. WISPs have been used to measure quantities in a certain environment, such as light, temperature, acceleration, strain, and liquid level. Additionally, given that the things to be network are all electric, i.e., the grid to be evolved to the smart grid, the powerlines can themselves serve as the communication medium. In this direction, several technologies have been developed. As an example, HomePlug AV (HPAV) [10] from the HomePlug Powerline Alliance represents the next generation of technology. Its purpose is to provide high-quality, multi-stream, entertainment oriented networking over existing AC wiring within the home. Moreover, Wimax and FDDI, although not implemented over powerlines, are examples of welldeveloped broadband telecommunication technologies that can be exploited to interconnect local networks across wide geographic areas. WiMAX (Worldwide interoperability Microwave Access) [11] is a technology capable of covering up to 50 Km with the data rate of up to 63 Mbps. FDDI (Fiber Distributed Data Interface) [12] is capable of providing a 100 Mbps optical standard for data transmission

4 in local area network that can extend in range up to 200 kilometers. These broadband telecommunication technologies can be utilized to extend any local network of things to wider areas when needed. 3.2 middleware The middleware is a software layer or a set of sub-layers posed between the low-level technological and the high-level application levels. Its feature of hiding the details of different technologies is fundamental to exempt the programmer from issues that are not directly pertinent to the focus, which is the development of the specific application enabled by the IoT infrastructure. The middleware architectures proposed for the IoT often follow the Service Oriented Architecture (SOA) approach. The adoption of the SOA principles allows for decomposing complex and monolithic systems into applications consisting of an ecosystem of simpler and well-defined components [1]. Relying on the physical layer technologies mentioned in the previous section, Fig. 2 shows the proposed architecture. Fig. 2. SOA-based architecture for the IoT middleware [1] Applications are on the top of the architecture, exporting all the system s functionalities to the final user. Indeed, this layer is not considered to be part of the middleware but exploits all the functionalities of the middleware layer. Service composition is a common layer on top of a SOA-based middle-ware architecture. It provides the functionalities for the composition of single services offered by networked objects to build specific applications. On this layer there is no notion of devices and the only visible assets are services. Service management layer provides the main functions that are expected to be available for each object and that allow for their management in the IoT scenario. A basic set of services includes: object dynamic discovery, status monitoring, and service configuration. A service repository is built at this layer so as to know which is the catalogue of services that are associated to each object in the network. The upper layer can then compose complex services by joining services provided at this layer. The IoT relies on a vast and heterogeneous set of objects, each one providing specific functions accessible through its own dialect. There is thus the need for an abstraction layer capable of harmonizing the access to the different devices with a common language and procedure.

5 Noticeably, the deployment of automatic communication of objects in our lives represents a danger for our future. For instance, embedded RFID tags in our personal devices, clothes, and groceries can unknowingly be triggered to reply with their ID and other information. This potentially enables a surveillance mechanism that would pervade large parts of our lives. The middleware must therefore include functions related to the management of the trust, privacy and security of all the exchanged data. The related functions may be either built on one specific layer of the previous ones or (it happens more often) distributed through the entire stack, from the object abstraction to the service composition, in a manner that does not affect system performance or introduce excessive overheads. 4 Applications of IoT in the Domain of Smart Grid Realization of IoT will definitely bring about multitude of applications some of which aren t even imaginable at this time. Our current surrounding objects are only primitively smart, most of which are not even equipped by a communicating device. Imagine those objects to be sensing the surroundings, communicating, and acting cooperatively. This implies a very different environment, where various applications within different domains, such as transportation, healthcare, and smart home/office, can be deployed. As mentioned earlier, a very practical and economic application of the IoT is in the domain of smart grid. The idealistic characteristics of smart grid include self-healing, mutual operation and participation of the users, perfect electricity quality, distributed generations and demand response, sophisticated market and effective asset management. All of these can be realized with the aid of the infrastructure envisioned for IoT; sensing/communication technology in IoT forms interactive real-time network connection between the users, corporation and power equipment to make data reading real-time, high-speed and two-way, thereby enabling deployment of smart grid control and monitoring applications. 5 Conclusion IoT is the huge network of interconnected objects. Enabling the smart grid can be accomplished in the same way as IoT or the internet is developed. IoT can be approached from object oriented and internet oriented perspectives. Assuming IoT is implemented, it should be viewed from the semantic oriented perspective in order to make it possible to deal with the large number of participating objects. As the short range enabling technologies for IoT/smart grid, RFID, WSN, WISP, Home Plug AV can be pointed out. Wimax and FDDI are the samples of broadband telecommunication technologies that can be utilized for the long-distance interconnectivity of networks of things as well. A standard middleware SOA-based architecture for IoT is presented, where service composition, service management, and object abstraction layers has been envisioned to enable dealing with the complexity of the IoT and developing the applications. Finally the application domains of IoT are mentioned, where enabling the communications needed for the smart grid is pointed out. References 1. Atzori, L., A. Iera, and G. Morabito, The internet of things: A survey. Computer Networks, (15): p Kortuem, G., et al., Smart objects as building blocks for the internet of things. Internet Computing, IEEE, (1): p

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