Over the last decade, smart meter technology has been installed in millions of residential and commercial users in the United States. Indeed, the U.S. is ahead of much of the rest of the world as utilities install smart meters across their service areas. For much of the industry, the primary business drivers for deployment have been cost reduction and energy savings. Cost reduction is relatively easy to justify because smart meters can reduce or eliminate the cost of physically visiting meters to collect readings for billing purposes. Advanced meters also include remote control switches to disconnect power as well as measure time-of-use, again without the need for physical visits. For energy savings, smart meters also provide a way for utilities to offer services to reduce consumption by managing individual appliances in return for a reduced rate. These technologies are proven, mature, and are widely deployed.
Less prominent, but just as important, is the role of smart meters in disaster recovery situations. It’s important to remember that smart meters are smart sensors. In addition to measuring energy usage for billing purposes, these sensors can provide valuable functions during disasters and during recovery. The following paragraphs outline a weather disaster scenario and the role that smart meters play in managing the situation. All of the capabilities described here are available and shipping with current smart meter technology.
As the storm rolls in, utility managers begin preparing. They start by comparing real and reactive power measurements on commercial and industrial (C&I) meters to see which commercial customers are still running large inductive loads. These loads indicate the activity of large electric motors and indicate which factories are running or shutting down. Smart meters provide these measurements over short periods, allowing utility managers to see which motor loads are shed prior to a storm. Information on factory shutdowns can be forwarded to public disaster coordinators. Next, the utility managers verify that known vacant buildings and houses have been disconnected from the grid by sending messages to smart meters. This action helps to prevent fires in case of major structural damage that would otherwise go unreported. If circuits are still active, disconnect commands can be sent to properly equipped smart meters and executed within seconds.
As the storm blows through, inevitable power outages begin to occur as power assets are disrupted. In some cases, distribution feeders are cut and power is restored automatically through another path. In other cases, however, distribution feeders are completely disrupted and power is lost. In still other locations, individual drops are cut, or transformers or other assets are damaged. These disruptions are extremely difficult to diagnose from a utility standpoint, because most utilities have little or no instrumentation on them. Similar to the fog of war, utility operators are overwhelmed by waves of information from telephone calls, first responders, and their own crews. It’s difficult to prioritize the work or to even know what kind of crew to dispatch to a particular location.
Luckily, smart meters can help. Smart meters use capacitors or batteries to store sufficient energy to send out a “dying gasp” message in the event of power loss. As this information is collected and analyzed a clear picture of the various outages begins to emerge. If a large group of meters goes out at the same time on the same distribution feeder, it’s likely that the feeder is damaged. Likewise, if all meters on a particular transformer or particular street report outages, the problem can be isolated to that location. Smart meters can even be used to detect disruptions to individual drop wires if neighbors still have power. More importantly, these disruptions can be located, analyzed, and acted on long before consumers even begin to report in with phone calls. This enables the utility and emergency coordinators to not only know where power is out, but predict when it will be restored down to individual addresses.
In particularly bad situations with significant building damage, it may be necessary for emergency coordinators to cut power to certain areas to minimize the risk of fire or injury due to energized lines until they can be inspected, but with the use of smart meters, power can be shut off remotely to individual addresses reported by emergency personnel.
If generation or feeder capacity is adversely affected during the storm, the utility may choose to shed load by implementing a demand response system. This enables the utility to send a message to turn off water heaters, air conditioners, and other appliances on a temporary basis. Normally, demand response systems are offered to consumers in exchange to favorable rates in order to balance and level loads; however, during a disaster situation, these same tools can be used to reduce the load on an otherwise stressed distribution system. Smart meters enable this capability by providing the communications path for the utility to send load commands to consumer appliances and verify their execution.
Finally, during the restoration phase of the disaster, smart meters are critical in reporting the resumption of power. Often there are nested outages in an area. When a utility crew notifies their dispatcher that power has been restored, it is a simple matter to verify that all the smart meters in that area are responding appropriately, but often a second, hidden outage is exposed deeper in the neighborhood by the smart meters. If that is the case, the utility crew can easily fix it while still onsite, rather than dispatching another crew later.
Smart meters are critical during disasters and during recovery. In preparation for an emergency, they can be used to disconnect empty buildings and detect large motor loads. During the disaster, smart meters provide practically real-time views of outages and disruptions before they are reported by consumers. The visibility they provide greatly reduces restoration time by giving operations personnel, field crews, and emergency coordinators a view of the restoration process.
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