General Overview of Smart Meters
Smart meters have two main components: an electronic meter that measures energy information accurately and a communication module that transmits and receives data. Smart meters are part of an advanced metering infrastructure (AMI) system that consists of smart meters, a communication network, and an IT application to manage the network and supply the required meter data and events to the utility’s various IT systems, including its outage management system (OMS). OMS allows a utility to better manage power outages and restoration events as well as reduce outage duration and costs.
Single Outage Events
Customers often call their electric service provider when they have problems with service in their homes. Some of these calls come as a result of a larger outage or utility problem. Many other calls are received for single customer outages where the problem exists on the customer’s side of the meter. Without a smart meter, these “no lights” cases are typically resolved during a phone conversation with the customer or, more often, during a trip to the customer’s residence.
Smart meters allow the utility to better understand if the outage is related to the utility service or is related to a problem within the customer’s premises. The utility can then take the proper action to resolve the problem in a timely and cost effective manner. Smart meters provide power status information automatically and on request. The automatically generated information includes the “power fail” indication when power is lost and “power restoration” indication when power is restored. A mid-western utility has seen a major benefit for this capability since installing smart meters. It eliminated almost all unnecessary no lights trips and helped customers address problems more quickly. The volume of no lights calls per year on average are 1.5 percent of the total customer base, and up to 30 percent of single customer calls were determined not to be an outage event.For instance, an average utility with one million customers would average 15,000 single no light calls per year which would equate to 4,500 outage events per year that are not utility-based outages.
Multiple Outage Events (Storms)
Multiple outage events come in just about every size and shape, from a single fuse to a massive outage caused by a major event such as a hurricane or an ice storm. All such outages have a negative impact on customers. Performing timely repairs and restoring service is a top priority for utilities. To restore power as efficiently as possible, the first step is to understand the scope of the current power outage. Most utilities use OMS to leverage all available information, such as customer phone calls, to define the number and location of affected customers.
Prior to smart meters and more advanced technology, the only input to OMS was the customers’ phone calls or the utility’s inspection crews. Customers’ phone calls will always be important, but in general, less than 20 percent of affected customers will report an outage for a variety of reasons, e.g., not being home or assuming that the outage has already been reported. As AMI gathers and sends data, OMS processes and analyzes it using the tracing and prediction analysis functions of a real-time distribution network model to determine the impact. OMS will make a prediction for the outage location and the extent, and dispatch appropriate crews to restore service based on the information available.
Smart meters send a last gasp message to the utility’s OMS system before the meter loses power. Not all last gasp messages make it, but usually enough messages are received to help the utility adequately determine which customers are affected. Smart meter outage data can increase the accuracy of outage predictions and help utility personnel to readily and accurately react to problems. The end result is that customers’ power is restored more quickly and utilities operate more efficiently and decrease costs.
Another benefit of smart meters is verification of power restoration. Restoration verification is accomplished when a meter reports in after being reenergized. This will provide automated and positive verification that all customers have been restored, there are no nested outages, and associated trouble orders are closed before restoration crews leave the areas. This reduces costs, increases customer satisfaction, and further reduces outage duration.
During a major event and prior to smart meter technology, it was common for utilities to dispatch crews to restore service to a customer whose service had already been restored. Utilities maximize the value of smart meters for service restoration through automated integration with AMI and OMS. This integration provides utility personnel the ability to visualize the full scope of damage and perform service repairs efficiently.
Summary of Outage Management Improvement Benefits
Utilities can use smart meters to determine if an outage is within the utility’s infrastructure or at a private residence, they can reduce unnecessary and expensive truck rolls. By gathering data from smart meters, utilities can quickly locate and repair utility-side problems. They use smart meters to find nested problems often caused by severe weather events. Benefits include a reduction in traveled miles, especially during severe weather, which improves worker safety and reduces vehicle carbon emissions. Smart meter data can help utilities visualize, analyze, and efficiently manage repairs, reducing outage times and costs while quickly and accurately verifying service restoration.
Utilities, their customers, and their regulators all want to reduce the number and duration of power outages. Tools that reduce the number of sustained outages include trimming trees, maintaining the grid, and deploying automation to restore service. Smart meters report many abnormal events, such as momentary outages on a per-customer basis, which are often a precursor of a grid failure. This information can help a utility predict where a future sustained outage might occur and be better prepared when it does occur.
Auto reclosing equipment, such as circuit reclosers, track the operation count, but it is often difficult to correlate these counts to the number of actual events and problems. By collecting detailed momentary outage data on a select number of meters, utilities can identify the number of events and pinpoint locations where there is a lot of activity. By mapping momentary data, utilities can determine where additional tree trimming might be needed or where some equipment may be defective. Utilities can then take corrective action to eliminate the problem and prevent a possible sustained outage.
If a utility is looking to improve its outage avoidance capabilities, then it must add mapping and analytical applications to maximize the value of smart meter data. These mapping and analytical applications are currently available, but not yet widely deployed for this particular application.
A benefit of smart meters working with mapping and analytical tools would be to verify the electrical phase to which a single-phase smart meter is connected. Smart meters’ data can then be used to verify and correct the utility’s electrical maps in its OMS. It is essential that the relationship between a smart meter and its electrical circuit is correct to ensure that the OMS predicts the scope of the outage correctly. Accurate understanding of the phase a meter is connected to will also improve the single phase loading. This leads to better asset utilization.
Outage History and Reliability Metrics
Smart meters timestamp all power up and power down events. Thus, precise outage times and durations can be calculated. Utilities can use this information for a more accurate calculation of their reliability metrics (SAIFI, CAIDI, SAIDI, etc.), identifying the overall performance as well as the best and worst performing circuits. Utilities can then develop the most cost effective action plan for future grid modernization investments.
Smart meters reduce power outage and restoration time, and are beneficial for single and multiple events. Smart meter data can be used with mapping and analytical applications to help prevent future power outages and ensure that the electrical maps in the OMS are correct for the most accurate predictions.
Grid resiliency, energy efficiency, and operational optimization have always been strong drivers for utilities. When integrated with distribution automation and grid reliability programs, investments in AMI will enable utilities to further reinforce and strengthen critical utility infrastructure before and during storms, reducing restoration costs and minimizing customer outages.
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