FLISR provides a smart brain
IN A POWER OUTAGE, RESTORATION TIME becomes the most imperative issue, from a customer's perspective. Automation, thanks to devices out on the feeders and a good, two-way telecommunications network reaching out from the utility's control room, can isolate the outage within minutes and reroute electricity routes around it while the issue is being resolved.
Fault location, isolation and service restoration, or FLISR, is a primary automated line switching application gaining traction with electric utilities. In fact, in a survey of utility executives on distribution optimization applications conducted last year by IDC Energy Insights, FLISR scored highest in terms of interest and technical feasibility, and was deemed likeliest (of four distribution optimization applications) to lead an adoption cycle starting this year.
Enabling a smart process
FLISR has been described as the smart brain at the control center, using remotely controllable devices to execute the smart decisions. It, and other automated applications, can alternatively be viewed as the heart of the system, operated remotely from the operations control center via the "arteries and veins" of an extensive two-way telecommunications network.
True to its name, FLISR performs this way. It:
- Detects that a feeder fault has occurred;
- Locates the damaged portion of the feeder between two remote controlled line switches;
- Isolates the damaged portion of the feeder by opening appropriate remote controlled line switches; and then
- Re-energizes undamaged portions of the feeder via the primary feeder source and one or more backup sources using remote controlled tie switches.
It's gaining traction with utilities that have deployed smart meters, according to IDC Energy Insights analyst Marcus Torchia, who earlier spoke with Intelligent Utility Daily editor-in-chief Phil Carson about FLISR's interest. "With smart meters and AMI (advanced metering infrastructure) in place, FLISR becomes a process, an application, that's more readily enabled because the meters act as sensors that can trigger an alarm that the power is out," he said. "With meters, FLISR becomes more accurate and restoration goes more quickly."
But implementation, Torchia said, requires greater effort than volt-VAR control, which scored higher on economic feasibility in the IDC survey. FLISR requires integrating a number of systems across operations, engineering, customer service and billing to get utility visibility out into the distribution grid.
Volt-VAR control, on the other hand, is operations-facing alone, meaning less integration and less cost to implement.
Putting FLISR to the test
Pacific Gas & Electric recently piloted FLISR in Rio Vista, the largest small town in California's Eastern Solano County, as part of its Cornerstone Improvement Program, authorized by the California Public Utilities Commission (CPUC) in 2010. Here, the longest rural electric circuits that serve the community of 7,300 residents are subject to being knocked out by extreme weather, tractor drivers who take out power poles and even birds that straddle the charged wires. In other words, a perfect test case for FLISR.
FLISR was piloted by the utility on 25 miles of circuits served by one substation in the Delta. The circuits deliver electricity to Rio Vista, Isleton and Clarksburg along the Sacramento River, as well as to the farms and ranches within the area.
But before the pilot was even launched, the FLISR technology was lab-tested and evaluated at PG&E's Smart Grid Test Center in San Ramon, according to Jonathan Marshall, PG&E's chief of external communications, who wrote about it extensively in the utility's NEXT 100 blog last spring. The test center's first smart grid project involved "the rapid design and construction of a three-circuit simulation to test and evaluate state-of-the-art FLISR systems," Marshall noted, before the FLISR devices ultimately chosen were installed on key urban and suburban circuits across its service area as part of the three-year Cornerstone Improvement Program.
"Currently, the typical switching time is about an hour," Kevin Dasso, PG&E's senior director of smart grid and technology integration, said as the FLISR technology was being lab-tested. "Our target is to do that in less than five minutes. The reality is that it usually takes about two minutes."
In the new lab, Dasso's technical team was able to thoroughly test out new FLISR devices and software under all manner of realistic scenarios, ironing out the risks of a full field implementation, Marshall reported.
Put to the test
Last September, the FLISR equipment in PG&E's pilot project was put to its first real-world test. On the morning of Sept. 12, a downed overhead line took out one of PG&E's two circuits to Rio Vista. Marshall says the FLISR equipment sized up the problem, quarantined the bad section and restored service to 1,774 of 2,294 customers in under two-and-a-half minutes.
"Based on typical repair times, that quick response slashed the number of affected customers by 77 percent and the number of minutes they were out of power by two-thirds,"
he later wrote. "This will be a big deal to many customers. An hour of downtime can cost businesses tens, even hundreds of thousands of dollars. But even if you're working from home, an hour lost can blow your deadline, costing you both money and aggravation."
Expanding FLISR equipment beyond the pilot area will provide economies of scale, adding up customer benefits with any outage. The Cornerstone Improvement Project's authorized budget through 2013 is approximately $360 million, with about half of the money to be used to help automate more than 400 of PG&E's 3,200 electric distribution circuits. The CPUC has also said it will take a fresh look at FLISR technology in 2014 with an eye to authorizing more upgrades if they prove cost-effective.
Reliability improvement important
A report on the value of distribution automation, prepared for the California Energy Commission by Navigant Consulting in March 2009, noted that reliability improvement is one of the most common reasons cited by utilities for implementing distribution automation. "Automatic or remote-controlled switches installed on distribution circuits enable utilities to isolate faults more quickly, and reduce the amount of time many customers are without power," the report stated. "This application, becoming known in the industry as `Fault Location, Isolation and Service Restoration' (FLISR), can yield significant reductions in outage minutes experienced by customers.
"By combining FLISR capabilities with advanced sensors and controls that enable automatic condition-based equipment maintenance, distribution automation could yield even greater reliability improvements."
Integration in larger pilots
Southern California Edison, San Diego Gas & Electric (SDG&E) and Southern Company, among others, are also expanding their FLISR pilots further into their larger coverage areas. NSTAR and EPB Chattanooga have large-scale implementations underway, as well.
SDG&E, for example, has been installing automated switching since 2008, with plans to have its entire distribution area covered by 2016. In addition, its feeder automation system technology (FAST) is part of an integration of five technologies it is piloting as a proof-of-concept Beach Cities Microgrid test.
Besides feeder automation system technology, the U.S. Department of Energy (DOE) component of the microgrid pilot includes distributed energy resources and volt-amps-reactive (VAR) management, advanced energy storage, the integration of outage and distribution management systems, and price-driven load management.
No glamor, but lots of workhorse intelligence
It's not glamorous, and it's usually discussed in the larger context of outage management, but FLISR technology is one of the next best steps a utility can take once intelligent meters and a utility-wide communications infrastructure are in place. The ability to localize an outage, quickly reducing larger-scale outages to more localized ones, minimizes the scope of the work necessary for the crews dispatched to verify and repair the identified fault on the circuit.
Its immediate benefits are observability and coordinated automatic control. As with many of the new technologies being implemented, the increased granularity of the data available means distribution operations can become increasingly more efficient. And the ability to locate the fault remotely turns into both reliability and savings benefits, narrowing the scope of work necessary by field crews for each event and reducing the number and scope of prolonged outages.
While FLISR technology, or fault response automation, can't automatically clear a hard fault, it can definitely both reduce the impact of the fault and narrow the scope of the work that needs to be done by the field crew, who would otherwise be patrolling along the entire feeder to locate the problem, and then manually restoring service to as many customers as possible before repairing the fault.
It's all about knowledge
Integrating FLISR with other distribution automation technologies, in short, gives system operators increased knowledge about the system, better data to deal with in terms of responsiveness and decision management, and the ability to improve both reliability and safety, too.
According to industry analysts, we'll be hearing a lot more about FLISR in the years to come.
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