An effective network infrastructure should be designed to support various applications, now and in-the-future. So, it is important to choose a “standard based” network with the potential to support future applications when they become available.
Internet Protocol (IP) or TCP/IP is the preferred choice network for utility applications, as it provides intelligent platforms to support video, telephony, SCADA and broadband services in an economical and effective matter.
A TCP/IP based AMI communication network can also bring many potential options to consumers, outside and inside the home. Appliances with sensors and processing capabilities can now communicate with control servers or gateways via the AMI. In-home devices will be able to request real time electricity usage data from the smart meter via a centrally controlled gateway and make decisions based on the real-time cost of power at any time slot. Consumers will be able to view and control their entire home electricity usage with a click on their mobile devices from office or in the car. Some utilities may even provide content or broadband services to their subscribers provided there is sufficient bandwidth. The demands of these types of advanced applications are driving the need for increased bandwidth to be carried within an AMI network.
Various media technologies can be considered to provide part or entire AMI network:
• Broadband over power lines (BPL)
• Power Line Carrier (PLC)
• Wireless (GPRS, 3G, WiFi, WiMax, proprietary RF)
• Private line (copper, fiber)
• Public dial-up
• Combination of the above
Recent technology advancement on BPL has made it an attractive solution for fast AMI deployment. BPL is a technology that allows TCP/IP based data to be transmitted over utility power lines. BPL is also sometimes called Internet over power line (IPL), power line communication (PLC) or power line telecommunication (PLT). The technology uses medium wave, short wave and low-band VHF frequencies and operates at speeds up to 200Mbps. BPL technology provides scalable two way data communication over existing power line infrastructure. In Table 1, we summarize the estimated bandwidth requirement for possible smart grid applications.
Power distribution lines are assets of electricity companies and naturally a great AMI resource which can be controlled and maintained by electricity companies themselves. By leveraging the power line infrastructure there are significant economical and manageability benefits to advanced metering infrastructure that utility companies are planning now.
The initial cost of implementation of BPL as the AMI communication network technology may be higher compared with narrow-band based PLC. However, high bandwidth and scalable functionalities of BPL add significant cost savings to the maintenance of AMI and implementation of future smart grid applications. Bi-directional broadband bandwidth offered by BPL supports wide range applications such as real time monitoring, video surveillance, SCADA, tele-protection and other consumer services, which all aim at improving customer satisfaction, operation effectiveness, and security (both for cyber and physical security). The system supports standard–based SNMP network management protocol which reduces maintenance cost tremendously. BPL also provides a cost-effective alternative solution for last mile broadband access to home and office buildings.
Like all IP based networks, there are many potential threats and vulnerabilities within an AMI network caused by interconnecting many cyber assets together. Utilities are now moving from a world of offline meters to a network of smart meters communicating every minute. Cyber security safeguard is an important consideration in the planning of AMI. BPL provides enhanced security by leveraging standard based DES/3DES encryption to ensure the protection of consumer data and AMI infrastructure.
Economical and flexible communication solutions for data collecting for low density remote rural communities could be a big challenge for planners. In most rural areas, cellular signal are not easily accessible as wireless coverage is much lower. Narrowband PLC system may provide an economical AMR solution but often lacks the real-time communication capability and reliability as it takes longer to collect data and failure rates are higher. Infrastructures built with BPL technology can solve many of the issues described here.
