Smart Grid

Smart grid technologies include the deployment of new measurement and communications equipment to enable real-time monitoring and deployment of energy throughout the grid. An important innovation with smart grid technology is the development of two-way communications between the consumer and utility company. Users are able to monitor not only their energy usage, but also the price of that energy based on time of day and overall system demand. For the first time, consumers are active participants in the energy distribution process. For the utility company, costly outages can be averted during peak demand by reducing supply for select customers with pre-arranged agreements that trade participation with favorable pricing discounts.

Basic Networks

Home area network (HAN) – which covers the communications between a building’s interior and a smart meter.
Field area network (FAN) – covers communication between the user’s smart meter and a concentrator (or aggregator).
Wide area network (WAN) – a high bandwidth backhaul communication link between the concentrator and the utility.

Although there is no standard set on the types of wireless technologies used in each coverage area, a typical setup might include the use of WiFi or Zigbee for the HAN, WiMax for the Field Area Network and Cellular, Satellite or WiMax for the backhaul. For each of these wireless segments, it is important to insure robust signal coverage as well as to avoid potential sources of interference.

Wireless Network Connectivity

Specific goals of the Smart Grid

Allowing consumers to actively participate in optimizing operation of the system
Reduce the environmental impact of the electric supply system
Add robustness to the network by introducing new self-healing technologies
Integrate ‘smart’ appliances and consumer devices as part of the system
Dynamic optimization of grid resources
Development of standards for communication and interoperability of equipment connected to the grid

Test Needs

The ability to analyze signal integrity in a wireless environment has long been realized by cellular carriers, satellite companies and other network providers as a crucial element in deploying and maintaining a secure system. As utilities deploy the Smart Grid with various wireless technologies, the need to access signal coverage and sources of interference will grow exponentially. Additionally, cable and antenna analyzers are needed to install, provision, maintain and troubleshoot wireless base station cable and antenna systems.

Utilities need to be able to analyze communication problems quickly and insure that their wireless network continues to run under a variety of conditions.

Cable and Antenna Analysis

The cable and antenna system plays an important role in the overall performance of the cell site. Small changes in the antenna system can affect the signal, coverage area and eventually cause dropped calls. Using portable cable & antenna analyzers to characterize communication systems can simplify maintenance and overall performance significantly. The return loss/VSWR measurements are used to characterize the system. If the match is outside the system specification, the DTF measurement can be used to troubleshoot problems, locate faults, and monitor changes over time.

Interference Analysis

Wireless communications systems must coexist in extremely complicated signal environments. This is particularly true at ISM frequencies, such as the popular 2.4GHz band used by technologies such as WLAN, Zigbee, and Bluetooth, which must all compete for limited frequency resources. Household items such as microwave ovens are also potential sources of interference. Additionally, interference can be generated by various cellphone frequencies, WiMax and other technologies. These environments are comprised of multiple wireless networks ranging from mobile communication services to specialized mobile radio and paging/broadcast systems.

Indoor Coverage Mapping

To plan and optimize wireless networks, utilities must identify the coverage their transmissions provide in a given geographical area. For indoor signal analysis in areas such as airports, train stations or office environments, coverage mapping allows the technician to easily identify coverage quality throughout any given facility. As the user walks through the coverage area, taking signal strength measurements is as simple as walking through the facility with the analyzer. Measurements of signal quality are automatically acquired, stored and made available for later post-processing, visualization and analysis. The technician can also receive real-time updates of signal quality by viewing the analyzer screen at any time during the process. In this way, network planners can identify areas were additional transmitters or repeaters may be needed to insure good signal quality.

Outdoor Coverage Mapping

Outdoor coverage mapping enables the utility provider to optimize the network by identifying signal coverage in an outdoor environment. Assisted with GPS, areas of relative signal strength can be automatically measured and precisely correlated with location. The analyzer can be set up to take automated measurements either as a function of distance or time. For distance, the technician can simply turn the instrument on, set the distance intervals where measurements are to be taken, and drive within the coverage area. The GPS receiver automatically determines the distance moved, triggering new measurements. Data can be displayed later in a variety of formats, including third-party vendors such as GoogleEarth™.

Summary

A large portion of the intelligence being incorporated into the Smart Grid is wireless, i.e. radios, sensors, concentrators and backhaul located through the grid. A big challenge for utilities is the development of two-way communication systems that can support a large range of applications and requirements. Anritsu is contributing to this effort with test and measurement instruments that make it easier and faster to enable Smart Grid communications.