Like most electric distribution utilities, Dominion Virginia Power monitors and reports on the reliability of its circuits. In Dominion's case, a list of 200 worst performing circuits is included in its annual filing with the Virginia State Corporation Commission (SCC), the commonwealth's utility regulatory body. After several years of filing these lists, it became apparent that the worst-performing circuits were perennials, continually appearing in the Top 20.

Dominion had no focused or systematic program in place to deal with circuits that were providing its customers with the worst service year after year. And although the utility has replaced crossarms and arresters here and there, those replacements did little to improve the overall performance of a circuit. Dominion's reliability management team realized individual circuit performance and system performance indices would not improve without a change in the paradigm. Moreover, they would most likely deteriorate over time.

During this same period, Virginia's regulatory landscape was changing. The 2007 re-regulation of Dominion's distribution business brought the utility back to a traditional rate-of-return model combined with performance-based incentive. The SCC was given the authority to reward or penalize Dominion up to 100 basis points based on customer service and operating efficiency, among other criteria. While reliability was not explicitly mentioned, the fact that the system average interruption duration index (SAIDI) was regularly reported and had the attention of SCC staff made it clear that system reliability was going to come under increasing scrutiny.

It should be noted that the primary driver behind this initiative was always the desire to improve service reliability and thus customer satisfaction. Poor reliability was seen as being inconsistent with business excellence, a core Dominion value.

Circuit Reconditioning

Given Dominion's desire to improve reliability, the utility implemented a comprehensive program in late 2007 aimed at improving the performance and storm resiliency of its overhead distribution system. Known as circuit reconditioning, the multiyear, multimillion-dollar initiative is focused on reducing outages while revitalizing Dominion's worst-performing circuits.

The circuit reconditioning program addresses areas of a circuit that are critical to sustained service levels. These areas are typically the three-phase mainline from the substation to a circuit tie. By improving the condition and operability of the circuit mainline, Dominion expects the majority of its customers on the circuit will have shorter and less frequent outages.

Integral to Dominion achieving its goal of reliability excellence, the circuit reconditioning program targets the most common causes of service interruptions, including tree damage, lightning, line material or equipment failure, and wildlife.

To make circuits less susceptible to the effects of these and other events, Dominion is taking several measures:

  • Tree and vegetation trimming (in excess of the regular cycle cuts)

  • Installing or replacing various electrical switching devices

  • Grounding and lightning arrester improvements

  • Replacing facilities such as crossarms and insulators

  • Installing and replacing poles

  • Replacing faulty conductors

  • Bringing poles up to new clearance standards.

Circuit Selection

Dominion's reliability team used Six Sigma methodology to select the circuits for reconditioning. System average interruption frequency index (SAIFI) and SAIDI statistics from 2004 to 2006 were the primary source of data for the initial list. From this data, the worst-performing circuits were identified and the outage causes examined.

Dominion did not believe circuit reconditioning would reduce outages caused by the public (for example, dig-ins and pole damage caused by vehicle accidents), so the utility placed its focus where the greatest gains could be expected — on weather outages and equipment failures. Using these data points, Dominion compiled a complete list of candidate circuits.

The utility selected three circuits as pilots for the program in order to discover any pitfalls in the process prior to entering into a full-scale reconditioning effort. Dominion completed 12 miles (19 km) of reconditioning by the end of 2007. The knowledge gained from these few miles allowed the utility to start 2008 with a fully funded and fleshed out program. In 2008, the goal of 400 miles (644 km) annually was established, with circuits drawn from the original list of poor performers.

Project Management

From the beginning, it was clear project management would be necessary to coordinate resources and materials on such a large scale. Dominion's project managers have managed and coordinated more than 900,000 man-hours of work since the program's inception. Although man-hours and cost per mile of reconditioning varied throughout the system, project managers were able to manage this massive effort while achieving Dominion's financial and operational goals.

Currently, most projects are running in the 550 man-hours per mile to 600 man-hours per mile range, although some have been higher due to urban conditions or reconductoring. The project management team is central to the program's success, focusing on securing design and construction resources to liaising with scheduling and resource management groups to produce results in the field.

Preparatory Activities

To reduce costs and unnecessary pole replacements, Dominion's reliability team has coordinated the inspection of approximately 17,000 poles on the distribution circuits selected for reconditioning. Osmose Utility Services Inc. was contracted to achieve this objective. Initial rejection rates were high, with approximately 7.3% of poles rejected in 2008. However, poles that needed to be replaced were identified using tried-and-trusted utility practices, removing the doubt some less-seasoned designers were experiencing.

Initially, Dominion's supply chain team was concerned with the materials needed for such a large-scale systemwide project, since design quantities from the first several circuits showed that reconditioning required significant amounts of material. The supply chain team made adjustments to accommodate this need, purchasing crossarms, crossarm braces, cutouts, fuses, fault indicators, line tension disconnects (switches) and insulators in significant bulk and shipping them to local offices that had active reconditioning projects taking place.

Steady Progress

Construction crews responsible for circuit reconditioning consist of both Dominion and contract resources. At the height of the effort, 64 overhead construction buckets (46 contract and 18 Dominion) were engaged on 17 circuits throughout the system. Safety is not only one of Dominion's core values, but its highest priority. Since the beginning of the circuit reconditioning program in 2007, all work has been completed without incident.

Dominion's executives have set aggressive goals to achieve mileage gains in excess of 1,000 miles (1,609 km) within three years of the program. In 2008, the first full year of the effort, 376 miles (605 km) of reconditioning was completed. In 2009, crews completed 405 miles (652 km), and more than 290 miles (467 km) were finished by the end of October 2010. Since the program's inception, 34 circuits have been reconditioned and 15 circuits were active in late 2010.

The nature of this program requires the early identification of future circuits, and Dominion's reliability team has earmarked circuits for 2011 and early 2012. Design has started already on 2011 work, and Dominion expects to go into 2011 with nearly 50% of the year's work designed and ready to go. Subsequent releases in early 2011 will provide the balance of the circuits to complete the planned 400 miles.

Customer Involvement

Customer communication has been an important part of the circuit reconditioning program. Since most of the work is done with the lines energized, customers are not usually aware of the improvements being made to the circuits that deliver their power. Dominion has mailed more than 115,000 letters to those affected by this work. These letters detail the program and encourage customers to provide feedback. An e-mail account was set up specifically for customer responses or questions.

Customers have provided valuable feedback relating to decreased service interruptions as well as updated account information.

From the outset of the circuit reconditioning program, Dominion has insisted on a robust measurement system to gauge its effectiveness. Granted, any initiative takes time to bear fruit, but early analysis has been promising. Dominion has been careful to isolate the performance improvements of circuit reconditioning from general system improvements. To do this, the utility compares the change in circuit SAIDI and circuit SAIFI with the change in those metrics for the office responsible for the circuit. While not perfect, Dominion feels it gives the best view of how a circuit is performing pre- and post-reconditioning.

The analysis includes circuits where work is 100% complete, and the results are fairly conclusive. Whether the utility is looking at a 12-month rolling number, pre-reconditioning versus post-reconditioning, or pre-reconditioning versus current data, the circuit SAIFI delta outperforms the office SAIFI delta every time. This is also true with Dominion's excluding major storms metric or the broader all-in measure.

Daily Focus

Since late 2007, circuit reconditioning has matured from an idea to being part of the daily work of many Dominion employees. It even has its own nickname, with the program known by all employees as “recon.” Funding is in place to continue at the 400-miles-a-year pace, and the program has visibility and support throughout the ranks, from linemen to senior executives.

The reliability management team is expecting reconditioning to evolve from a program focused on mainline and performance to one that is more inclusive of tap lines and that attempts to objectively include some condition-based criteria in circuit selection. As Dominion works down its list of worst-performing circuits, obvious choices become few as performance tends to be homogenous. However, the focus of the program will continue to be the desire to fulfill Dominion's mission of providing service that reflects business excellence and exceeds customer expectations.


Les Carter (les.m.carter@dom.com) is manager of system reliability for Dominion Virginia Power's distribution system. He has held various financial and managerial positions at Dominion, and prior to joining the utility, he worked in the construction, banking and consulting fields. His holds a bachelor's degree in construction management from Brunel University in London, as well as a MBA degree and a master's degree in public management from the University of Maryland in College Park.

Companies mentioned:

Dominion Virginia Power www.dom.com

Osmose Utility Services Inc. www.osmoseutilities.com