Chugach Electric builds photographic database of its transmission line structures
Chugach Electric Association is taking advantage of high-resolution photography and searchable databases to enhance its ability to troubleshoot and maintain hundreds of miles of transmission line.
Chugach has contracted with Haverfield Corporation of Pennsylvania to provide an up-to-date record of more than 2,000 transmission line structures using photographs. An inspector in a specially equipped helicopter takes a series of photos from multiple vantage points as the helicopter hovers around each structure. Up to 10 photos are taken of each structure. The resulting pictures are extremely sharp - and allow Chugach personnel to zoom in and scroll around the photographs searching for potential problems. By identifying issues early on, crews can do the maintenance work necessary to prevent a disruption of service.
"Do you see where that cotter pin is missing on that lock pin?" said Chugach Operations Director Bill Bernier from his office as he pointed to a close-up photograph of the hardware holding one wire in a 230,000-volt circuit more than 60 feet above the ground in a remote area on the west side of Cook Inlet. "That's an outage waiting to happen. Without these photos, we probably wouldn't have spotted that before it pulled apart and fell onto the tower. We had an outage last year from something just like that."
Most of the structures being inspected are outside of Anchorage in areas with limited road access. Chugach may elect to have Haverfield record a section of transmission line along Tudor Road as well.
Depending upon the type of structure, a series of 5-to-ten photos is being taken of each tower or pole and their attached hardware and wire. It requires careful coordination between pilot and photographer to safely collect the needed photographs from the right angles. In compliance with safety codes and statutes, the helicopter must stay 20-to-30 feet from each structure.
The work requires not only special equipment, but special skills as well. Haverfield brought its own helicopter to Alaska on a cargo plane from its home base in Carroll Valley, Pa. The Hughes 500D helicopter is equipped with a digital hi-resolution camera and gyro-stabilized binoculars that allow inspector/photographer Larry Graham to capture a detailed record of each structure. Pilot Randy O'Neill has logged more than 10,000 hours of this kind of specialized flying.
Chugach will load the photos from the project into its geographic information system and document both the current condition of the equipment and needed maintenance on each structure. With the information in its GIS database, Chugach will be able to design an efficient, preventive maintenance program. The information will allow the utility to prioritize projects and coordinate similar projects within a geographic area.
The current project is significantly different than what Chugach has been doing. Chugach regularly inspects every mile of its transmission system twice a year. Chugach patrols its more than 400 miles of transmission line by having a lineman scan with image-stabilizing binoculars looking for obvious trouble spots from a helicopter. In addition, when Chugach crews are doing maintenance if they find a particular problem in an area, they will do climbing inspections of adjacent structures to see if the problem is repeated.
While the prior visual inspections were effective in finding many problems, they did not provide the same detailed record that will be captured by the current project. It is a cost-effective way for Chugach to baseline the condition of its transmission structures, spot problems and capture a visual record for future reference. The project is being done for a fraction of the cost of what it would take to compile the same data by having workers climb, inspect and photograph each structure.
The $200,000 project started July 7 and is expected to be completed by mid-August.
Chugach is the largest electric utility in Alaska, providing power for Alaskans throughout the Railbelt through retail, wholesale and economy energy sales.