A powerful windstorm swept across Vermont in April 2007. It did more damage to Central Vermont Public Service's system than any storm in the utility's history. But, Central Vermont Public Service (CVPS; Rutland, Vermont, U.S.) was ready for it, thanks to advance warning from a local contracted weather forecaster. And, when calls started pouring in from some of the 67,000 CVPS customers left without power, the utility was ready for that, too, thanks to an automated outage management system (OMS) implemented by Intergraph Corp. (Huntsville, Alabama, U.S.).

The restoration effort proved to be the largest in CVPS's history. With guidance from the OMS and assistance from 105 outside line crews, CVPS was able to restore power to 50% of the customers less than 48 hours after the storm and to all customers within five days. The utility estimates that without the OMS the average outage duration would probably have been twice as long, and CVPS would have incurred at least US$1 million in additional expenditure on outside crews.

A TRADITION OF TECHNOLOGY

CVPS supplies electricity to 158,000 residential and commercial customers in 152 communities spread throughout the Green Mountain state. Although the majority of its meters are located in the southern two-thirds of the state, pockets of additional customers reside in the northern area close to the Canadian border, effectively making the entire state part of the utility's service territory.

CVPS may be considered small in terms of total meters served, but the utility has always taken pride in staying at the forefront of automation and information technologies. In 1997, it implemented the Intergraph FRAMME package as its facilities management system to maintain a digital connectivity model of the entire distribution network. After a decade of successful service, CVPS is currently upgrading this system.

In addition, the CVPS T&D Operations and Engineering Group spearheaded development of a homegrown work management system (WMS) in 1996 to oversee design, scheduling, construction, and posting of all distribution maintenance and capital work. As work is completed by the field, data/facility management technicians (DTs) input detailed utility equipment and facilities data into the WMS. Information relating to these equipment repairs and installations is transmitted weekly from the WMS to the facilities connectivity model via an interface. The utility also maintains a customer information system (CIS), which interfaces with the facilities management and work management systems, as well as the OMS.

In 1999, CVPS became an early adopter of automated outage management technology when it implemented Intergraph's InService OMS package. InService integrated directly with the utility's existing facilities management system to provide real-time analysis of conditions across the distribution network. This allows the Resource Scheduling Group to optimize network usage during normal operations and to trace faults back to their source during outage events.

READY FOR THE STORM

In April 2007, CVPS knew from weather reports that one of New England's famous nor'easters was heading toward Vermont. The local weather forecaster predicted 70-mph (113-kmph) winds in the CVPS territory. This advance warning gave the utility nearly four days to make sure all of its 45 line crews were on call and to notify mutual-aid utilities as far away as Connecticut and Ontario, Canada, that CVPS might need outside help to recover from the damage that was sure to come.

Ninety percent of Vermont's bad weather comes from the west, but this nor'easter blew in from the opposite direction. Trees are not accustomed to high wind speeds and heavy loadings from this direction. As a result, CVPS anticipated extensive outages from power lines downed by fallen trees.

The storm lived up to expectations and even threw in a few microbursts to keep things interesting. After an intense four or five hours, the nor'easter passed, and the CVPS service territory recorded power outages to more than one-third of its customer base, caused by 2000 instances of downed lines, broken poles, and damaged distribution and transmission equipment. The only good thing about the storm was that it ended quickly without lingering weather disturbances, allowing CVPS to begin restoration immediately.

INTO THE RESPONSE

During and after the storm, customers called the utility to report outages in their areas. An interactive voice-response (IVR) system gave them the option of talking to a customer care advocate (CCA) or simply choosing “power outage” from a recorded menu selection. The IVR fed the outage reports into the CIS, which was also being directly accessed by the CCAs, who collected outage details.

The CIS database identified each customer by name or phone number and searched its files to link that caller's meter location with the appropriate electric line and pole. This line and pole identification, along with specific outage causes noted by call takers, was passed directly from the CIS to the OMS for processing.

Based on the flood of incoming calls, the OMS continually ran fault traces on the network connectivity models to narrow each outage down to a specific line segment, line, fuse, transformer or substation. The OMS collected a large volume of data in a hurry and showed CVPS the scale of its problem.

The OMS gets the utility to where it can send a crew to the right location. The utility has a centralized dispatch room in Rutland with up to 16 workstations active during a storm like the 2007 event. Each dispatch workstation has access to the digital OMS map display, which shows the facilities network overlaid on a transportation grid.