19-07-2011, 03:17 PM
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INTRODUCTION
A smart grid is a form of electricity network using digital technology. A smart grid delivers electricity from suppliers to consumers using two-way digital communications to control appliances at consumers' homes; this could save energy, reduce costs and increase reliability and transparency if the risks inherent in executing massive information technology projects are avoided. The "Smart Grid" is envisioned to overlay the ordinary electrical grid with an information and net metering system, that includes smart meters. Smart grids are being promoted by many governments as a way of addressing energyindependence, global warming and emergency resilience issues.
Advanced Metering Infrastructure (AMI) provides consumers with the ability to use electricity more efficiently and provides utilities with the ability to monitor and repair their network in real time. Smart grid communication technologies must allow the power grid control center to access each meter connected to it interactively several times in a second, offering dynamic visibility into the power system. Some implementations exist of this infrastructure using wireless technologies. The use of the existing infrastructure; i.e.the low voltage power-lines for high speed, reliable simultaneous two way communication between the head end (i.e. the nearest power grid communication hub) and meters located on different parts of the network is explored. Data communication through the power grid offers several advantages in that new infrastructure is not required, and in principle even enclosed sensors not accessible by wireless technologies can be read.
Chapter 2
AMI COMMUNICATIONS NETWORK SRUCTURE
FIGURE 1
The backbone of the smart grid is an Advanced Metering Infrastructure (AMI). This consists of a grid management system, so-called “smart meters” and a communications network binding it together. The basic structure of the AMI communications system is shown in Figure 1. Each residence contains a smart meter, which is equipped with short haul communications that service the local area. The local area usually consists
of up to 500 residences, which is generally the number of residences connected to an LV transformer. Information from the meters is collected at intervals by the data collection unit through the short haul communications. Information is then collected from the data concentrators through long haul communications where it is stored in a centralised database. The long haul communication path is commonly implemented as some form of internet connectivity like GPRS. The centralised database and control receives interval readings such as power usage and can make decisions about the need for load shedding to protect the power grid.
Currently, the most viable technologies to realize the AMI short haul communications network are wireless and power line communication (PLC) technologies. Power distribution companies have traditionally been interested in PLC because it represents the most cost effective solution and does not require additional investment in communications infrastructure.
Narrowband Power Line Communication (PLC) systems appear to be well suited to implement the smart grid network due to their inherent low costs. However, the characteristics of the power line channel within the frequency range of 9 to 490 kHz used by narrowband are extremely complicated and thus present a number of communication difficulties, limiting the potential of narrowband PLC. For example, recent trials raised major concerns about the reliability and throughput of narrowband communication systems.As a result, PLC technologies were not considered further for the Victorian AMI network. Such outcomes highlight the need for greater reliability and higher throughputs from PLC systems.
INTRODUCTION
A smart grid is a form of electricity network using digital technology. A smart grid delivers electricity from suppliers to consumers using two-way digital communications to control appliances at consumers' homes; this could save energy, reduce costs and increase reliability and transparency if the risks inherent in executing massive information technology projects are avoided. The "Smart Grid" is envisioned to overlay the ordinary electrical grid with an information and net metering system, that includes smart meters. Smart grids are being promoted by many governments as a way of addressing energyindependence, global warming and emergency resilience issues.
Advanced Metering Infrastructure (AMI) provides consumers with the ability to use electricity more efficiently and provides utilities with the ability to monitor and repair their network in real time. Smart grid communication technologies must allow the power grid control center to access each meter connected to it interactively several times in a second, offering dynamic visibility into the power system. Some implementations exist of this infrastructure using wireless technologies. The use of the existing infrastructure; i.e.the low voltage power-lines for high speed, reliable simultaneous two way communication between the head end (i.e. the nearest power grid communication hub) and meters located on different parts of the network is explored. Data communication through the power grid offers several advantages in that new infrastructure is not required, and in principle even enclosed sensors not accessible by wireless technologies can be read.
Chapter 2
AMI COMMUNICATIONS NETWORK SRUCTURE
FIGURE 1
The backbone of the smart grid is an Advanced Metering Infrastructure (AMI). This consists of a grid management system, so-called “smart meters” and a communications network binding it together. The basic structure of the AMI communications system is shown in Figure 1. Each residence contains a smart meter, which is equipped with short haul communications that service the local area. The local area usually consists
of up to 500 residences, which is generally the number of residences connected to an LV transformer. Information from the meters is collected at intervals by the data collection unit through the short haul communications. Information is then collected from the data concentrators through long haul communications where it is stored in a centralised database. The long haul communication path is commonly implemented as some form of internet connectivity like GPRS. The centralised database and control receives interval readings such as power usage and can make decisions about the need for load shedding to protect the power grid.
Currently, the most viable technologies to realize the AMI short haul communications network are wireless and power line communication (PLC) technologies. Power distribution companies have traditionally been interested in PLC because it represents the most cost effective solution and does not require additional investment in communications infrastructure.
Narrowband Power Line Communication (PLC) systems appear to be well suited to implement the smart grid network due to their inherent low costs. However, the characteristics of the power line channel within the frequency range of 9 to 490 kHz used by narrowband are extremely complicated and thus present a number of communication difficulties, limiting the potential of narrowband PLC. For example, recent trials raised major concerns about the reliability and throughput of narrowband communication systems.As a result, PLC technologies were not considered further for the Victorian AMI network. Such outcomes highlight the need for greater reliability and higher throughputs from PLC systems.
