Electric utilities are increasingly utilizing the Internet of Things (IoT) to monitor, coordinate and synchronize the transmission and distribution of electrical power over large geographic areas. An earlier article discussed how National Grid uses the IoT to monitor and keep distant power generating stations in phase. This article will focus on how electrical utilities are utilizing the IoT to improve monitoring capabilities on the very outer edges of the grid where electrical power is consumed by homes and businesses.
Challenges on the grid's edges arise from the limitations of traditional electric meters that don’t make power consumption information available until a meter reader manually enters the information into a database. Today, electrical utilities want to track power consumption in real time to better manage and optimize power generating sources and the transmission and distribution network. Another advantage of real-time tracking, is the time crews could save restoring power after an outage by quickly and easily determining which parts of the distribution network were operating and which were not. Finally, traditional meters measure only the electricity that is consumed while today it’s increasingly becoming necessary to also track power generated by users through other methods such as rooftop solar that are fed onto the electrical grid.
Electrical utilities are addressing these challenges by migrating to smart meters with wireless communications capabilities that continuously transmit bi-directional energy flows at the individual user level. Understanding how demand is changing minute-by-minute or second-by-second helps utilities manage power generating, transmission and distributing resources more efficiently. Utility restoration crews can see the status of the electrical network in near real time so they can pinpoint the location and extent of outages, resolve problems on the first visit, and avoid unnecessary truck rolls.
Smart electric meters are already installed in millions of homes and businesses in North America, Europe and Asia and electrical utilities would like to roll them out to more customers as soon as possible. The greatest obstacle is the expensive and complicated networking infrastructure that has typically been required in smart meter installations. When installing thousands or even millions of meters, it is not feasible to equip each smart meter with its own cellular connection. Instead, the most common approach is to use available spectrum, such as industrial, scientific and medical (ISM) radio bands, to upload data to gateways with a typical ratio of one gateway per 10 meters. These gateways are then connected through repeaters or routers to the core network.
This approach requires a fairly complex and expensive networking infrastructure which has delayed smart meter proliferation in many areas. The need for many gateways, routers and repeaters adds considerable cost beyond the meters. Designing, configuring and installing the network is another major expense.
Another potential problem is that the radio environment continually changes due to temperature changes, obstacles, and atmospheric conditions. Smart meters are often installed deep indoors which increases data transmission challenges. Each meter typically communicates with a single gateway so it’s common for a smart meter to have problems communicating with its designated gateway. The customer’s electricity consumption can always be uploaded at a later date when conditions improve but losing communications with large numbers of meters on a regular basis reduces their value in managing the grid and restoring power.
A smart meter project in Norway by Aidon, a leading provider of open-architecture based smart metering systems based in Finland, is overcoming these obstacles. The key difference in this installation is the use of an automated multi-hop mesh network designed by Wirepas, a Finland-based networking technology company. In this new style network, e ach smart meter communicates with its neighbor, passing data from device to device, until it is finally delivered to the gateway. Aidon built the meters and licensed the radio technology from Wirepas.
Each device has multiple routing options (the place where data is sent next) and multiple gateways (the ultimate destination of the data). Every meter is a possible routing point for forwarding data. Each meter contains intelligence that optimizes the topology of the network continually to adjust to radio spectrum changes. If radio transmission conditions are bad in a certain area, the meters will automatically reconfigure themselves to send data by another route. Individual devices decide the best actions locally, no central network management needed. Different operating parameters can be changed to provide tradeoffs between bandwidth, latency range and power consumption.
The ability to pass data from meter to meter greatly reduces the number of gateways required. One gateway per 1000 meters is possible but in practice one gateway per 150 or 250 meters is often used to build redundancy into the system. The gateways are located at existing connection points to the core network such as cell phone base stations so there is no need for routers and repeaters. This type of network requires minimal design configuration and installation because the network automatically configures itself. New meters are automatically recognized by the other meters and configured into the network. All of the intelligence is built into the Wirepas connectivity software so the physical layer can be chosen freely based on the application requirements.
“The rule of thumb, generally speaking, is that if a smart meter costs about $100, it will require about $300 in additional costs such as routers, repeaters, network planning, field installation, etc. for a total installed cost of about $400 including some years of data plan costs,” said Teppo Hemia, Chief Executive Officer at Wirepas. “Our target in this application is to reduce the total installed cost by 20%-25% or down to $300.”
With the lower cost and higher performance of this technology, Aidon has won a contract to replace 1.5 million electrical meters with smart meters in Norway. The company has also won orders to begin replacing up to 4 million meters in Sweden.
Image of Aidon 6000 series 3- and 1-phase Energy Service Devices courtesy of Aidon.