AMERICAN ELECTRIC POWER (AEP) OPERATES MORE THAN 2000 MILES (3219 KM) OF 765-KV TRANSMISSION LINES IN THE UNITED STATES, from the southeastern shore of Lake Michigan to the rolling red clay Piedmont country of central Virginia. Yet, for a critical 90-mile (145-km) 765-kV transmission addition nearing completion in just a few months in AEP's southern West Virginia and southwest Virginia service areas, it's as though AEP (Columbus, Ohio, U.S.) started from scratch, challenging assumptions of the past and taking a fresh look at all aspects of this project: engineering, right-of-way management, procurement, scheduling and construction practices.

AEP's Wyoming-Jacksons Ferry line — the first major high-voltage supply line since 1973 — stretches from its Wyoming station near Oceana, West Virginia, south to Jacksons Ferry Station near Wytheville and Pulaski, Virginia. Two major radial extensions of AEP's 765-kV system were built in Virginia, but the new line is the first transmission line in more than 30 years from AEP's major generating plants on the Kanawha and Ohio rivers to southern West Virginia, western Virginia and eastern Kentucky. But not for want of trying.

A SLOW START

AEP announced plans in March 1990 for a 110-mile 765-kV line to Roanoke, Virginia. This proposal evolved into the Wyoming-Jacksons Ferry line during regulatory proceedings in Virginia. An exhaustive, up-and-down permit review process before two state utility commissions and the U.S. Forest Service (USFS) consumed almost 13 years. As early as December 1995, the State Corporation Commission (SCC), Virginia's utility regulatory body, issued an interim order in which it cited a “compelling need for additional capacity” to serve southwest Virginia and said that the proposed transmission line was the best alternative to meet the need. Finally, in December 2002 the USFS issued an environmental impact statement permitting 11 miles (18 km) of the line to pass through the Jefferson National Forest in western Virginia. Following appeals and litigation by opponents of the line, as well as the SCC's approval of AEP's final line design and right-of-way clearing plans and early right-of-way acquisition, right-of-way clearing began in December 2003. Electricity is scheduled to begin flowing by late June 2006. The expression “started from scratch” was used to make a point about AEP's innovations in connection with this largest transmission project currently underway in the United States. In reality, AEP was building upon almost 40 years of experience in the operation of 765-kV lines and almost 90 years of designing, building and operating transmission lines. AEP's first major transmission line was the Windsor-to-Canton 138-kV line from a mine-mouth generating plant in the northern panhandle of West Virginia to the vital steel industries of northeast Ohio during World War I.

IT STARTS WITH THE WIRE

With the Wyoming-Jacksons Ferry line, it all starts with the wire (795 kcm ACSR 45/7 - Tern), and more specifically, with the number and arrangement of conductors. AEP's existing 765-kV system consists of two types of conductor bundles per phase. Each phase has four conductors. When AEP started its 765-kV system in the late 1960s, each of the three phases consisted of four 954 kcm - Rail wires at a diameter of 1.165 inches (3 cm) per wire. When additions were made to this system in the mid-1970s, a larger (1352 kcm - Dipper) wire size (1.385 inches [3.5 cm]) per wire was selected and used for the remainder of the system. The result was 1098 miles (1767 km) of the original size and 924 miles (1487 km) of the larger wire, until Wyoming-Jacksons Ferry.

To improve efficiency by reducing corona and to reduce audible noise associated with the existing four-wire configuration at higher elevations in foul weather, AEP analyzed and tested various wire configurations and decided to install a new six-wire 795-kcm bundle on the new line. In fact, in 1995 the company installed a 1-mile (1.6-km) section of six-wire bundles on its Jacksons Ferry-Axton line in the Blue Ridge Mountains near Floyd, Virginia, south of Roanoke. This trial section of line proved invaluable during the siting and hearing process as local residents and state regulators were able to observe first hand how the new design cut the audible noise nearly in half from older generations of 765-kV lines.

Actual operation of this section of line and lab tests of the new design confirmed its improved operation; this important threshold decision begat a whole series of snowball actions.

Among the initial challenges associated with the new six-wire design was how to arrange the six conductors. What would be the most efficient shape or geometry of the six wires? With four wires, it was fairly simple, a square. Only the spacer-dampers changed with the four-wire design. Initially, a coiled wire spacer in the shape of a square was employed. Later, a stronger, solid X-shaped spacer was used to replace damaged square spacers.

Where the existing four-wire arrangement measures 18 inches (46 cm) per side, the new bundle — in the shape of a symmetrical hexagon — is held in place by a 30-inch (67-cm)-diameter spacer-damper. Of course, the new design was chosen only after rigorous lab and field testing for strength and corona.

New conductor bundle geometry and spacer hardware drove the next challenge — electrical clearance from the tower structure itself. This required new hardware and new connections. And these required design and testing.

STRUCTURES ARE NEXT

AEP's existing guyed-V aluminum and self-supporting four-legged steel towers have proven to be a very efficient and acceptable design. The high cost of aluminum, and the fact that the market for aluminum tower construction had dried up, drove the company to galvanized steel for its guyed-V towers on the Wyoming-Jacksons Ferry line. While the same basic structure geometry was retained, a new family of structures was designed to incorporate new connections and details.

Prototypes of six new structure designs were assembled at the Electric Power Research Institute (EPRI) Solutions test facility in Haslet, Texas, U.S. These six structures represented a sample of the 12 types of towers used for the actual line. These prototypes were tested under varying loading conditions at the EPRI facility. Incremental improvements were made as a result. This type of structural testing is a balance between economics and engineering. The objective is to reach a level of comfort and confidence that a certain design, at a reasonable cost, will work.

AEP's existing 765-kV system uses some 2.5 million ceramic insulators. The company invited bids for both ceramic and polymer insulators. AEP has used polymer insulators selectively in some applications and extensively on its 345-kV transmission system serving its western service area in Texas, Oklahoma, Arkansas and Louisiana.

After an exhaustive analysis of the risks of using the new material and the costs and benefits of polymer insulators, AEP opted for polymer on the 223 guyed-V towers and 70 dead-end towers because it is less expensive, lighter and easier to handle. Ceramic insulators were installed on the 40 self-supporting suspension towers.

AEP's guyed-V towers use four stranded steel guys that are anchored by grouted strands (up to a 1.625-inch [4.128-cm] diameter) at a depth of 55 ft to 90 ft (17 m to 27 m) into soil and bedrock in the mountainous terrain of West Virginia and Virginia. This is a unique design developed by AEP for earlier generations of 765-kV transmission construction.

AESTHETICS AND ACCESS

Because of the protracted 13-year permitting and siting approval process involving regulatory commissions in Virginia and West Virginia and the USFS and local opposition to this project, building the line itself would require great care and sensitivity. AEP engaged a team of land-use experts from Virginia Tech and West Virginia universities who went through a significant process of analysis to recommend a 1000-ft (305-m)-wide corridor that minimized environmental and visual impacts to a landscape with cherished scenic and cultural values. They hiked and drove thousands of miles observing, taking notes and snapping photos, and they created computer images of towers imposed on the landscape to simulate impacts. Working with property owners and regulatory agencies, AEP engineers selected an optimum 200-ft (61-m)-wide right of way within the 1000-ft corridor.

AEP selected PAR Electrical Contractors Inc. (Kansas City, Missouri, U.S.), part of Quanta Services Inc., as its line construction contractor and brought PAR in early as a partner in construction preplanning. Due in part to the sensitivities cited previously regarding land-disturbing activities, AEP decided to award separate specialty contracts, one for right-of-way and tower site clearing (Phillips & Jordan Inc.; Wilmington, North Carolina, U.S.) and the second for access road construction and maintenance and land reclamation (Orders Construction Co.; St. Albans, West Virginia).

AEP had committed during the permitting process to minimize clearing, that is, to remove only tall-growing incompatible species and leave lower-growing species and to selectively apply herbicides exclusively by hand from the ground in the future. For example, the right of way was not cleared where conductor-to-ground clearance exceeded 100 ft (30.5 m).

The road subcontractor used, and in some cases improved, existing roads for access to tower sites. In all, 160 miles (257 km) of new roads were constructed in the mountainous terrain. The road contractor was also responsible for maintaining countless public and private roads during construction.

While cranes were used primarily to erect towers, helicopters were used to transport workers and materials to these sites, as well as for many other uses. In fact, helicopters were used wherever possible, particularly for completing nine guyed-V towers in inaccessible and restricted access areas, including one tower site in a roadless area of the Jefferson National Forest. Helicopters also were invaluable in transporting and setting guyed-V tower masts. In addition, they were used for hanging insulators and other hardware, replenishing wire buggies with spacer-dampers, flying and threading lead lines, and transporting steel bundles and conductor reels.

INNOVATION FOR THE FUTURE

The Wyoming-Jacksons Ferry line represents a solution to the need for additional electrical capacity in a part of AEP's service area. But innovations embodied in the physical aspects of the line — new wire bundle design and new tower series — confirm a commitment on AEP's part to push beyond the status quo and provide technical leadership for the electric utility industry. As AEP electrical engineers, high-voltage system planners and transmission engineers undertook the task of designing this new line in 1991 by looking to improve on the past, future transmission planners will look to advances made with Wyoming-Jacksons Ferry as their launching pad.

EDITOR'S NOTE

This is the first in a series of articles on AEP's Wyoming-Jacksons Ferry 765-kV project. Future articles will highlight construction, engineering and the six-wire bundle configuration used on the project. More information about the Wyoming-Jacksons Ferry project can be found online at www.apcocustomer.com/news/765kv/default.asp.

Jim Haunty served as vice president of Transmission Capital Improvements for AEP until he retired on Dec. 31, 2005. He was responsible for engineering, design, construction and project management for the company's 11-state transmission line and T&D substation system capital project. After service in the U.S. Navy, Haunty entered this industry in 1967 with (at that time) AB Chance Steel Poles Constructors Division (Houston, Texas). His AEP career first began in late 1969 when he started with Columbus Southern Ohio Electric (CSOE) as supervisor civil engineering design. He left CSOE and returned in 1974, and has since held a variety of management positions with AEP. Haunty holds a BSCE degree from Purdue University in West Lafayette, Indiana.

Experts Validate Need for Transmission Line

The winter of 2005-2006 should be the last one that customers of American Electric Power (AEP) operating companies in southern West Virginia and southwest Virginia have to live without a much-needed, long-proposed and long-delayed major transmission line now under construction. AEP's Wyoming-Jacksons Ferry 765-kV line is scheduled for completion in a few months following a two-and-a-half-year construction project. Electricity should start to flow on the 90-mile (145-km) line in late June 2006.

Announced in 1990, the line — originally a 110-mile line (177 km) to Cloverdale Station at Roanoke, Virginia — had been proposed by AEP system planners many years beforehand to meet utility industry reliability standards. Despite its need having been recognized by two state regulatory agencies and all their outside consultants, routing and permitting issues delayed approval of the line for many years.

In its order approving the line and routing in May 2001, the Virginia State Corporation Commission (SCC) acknowledged that AEP's filing had engendered a protracted and highly contested proceeding, and that the original and rerouted corridors had attracted substantial and understandable opposition. At the same time, the SCC acknowledged that the existing transmission system in southwest Virginia was seriously overloaded. The SCC accepted the hearing examiner's finding that 32 different system operating contingencies violated single- or double-contingency criteria, and provide clear and compelling evidence that the situation was critical.

AEP's Virginia service area is transmission dependent. The last major transmission reinforcement for the area came in 1973 with the completion of the Jacksons Ferry-Cloverdale 765-kV line. The region is a large importer of power from northerly AEP plants. And the gap between regional generation and customer load and peak demands more than doubled between 1973 and 1996.

In order to eliminate the gap and provide reliable transmission capability for future growth that meets industry standards, AEP proposed extending its 765-kV system from Wyoming Station in West Virginia to Virginia. By the time the new transmission line is in service in mid-2006, transmission planners estimate that the peak demands will be more than 180% greater than the 2512-W peak of 1973. Many computer models and contingency scenarios indicated the loss of major transmission facilities at peak load conditions could result in unscheduled outages and cascading blackouts.

Key Events in the History of AEP's Wyoming-Jacksons Ferry 765-kV Transmission Line

March 1990

AEP announces plans to build 130-mile (209-km), 765-kV transmission line from its Wyoming station near Oceana, West Virginia, to its Cloverdale Station near Roanoke, Virginia. The proposed line would be the first major reinforcement of the bulk transmission system in the area since the original system was completed in 1973.

March 1991-February 1993

Applications for permits and certificates filed with utility regulatory agencies in Virginia and West Virginia and the U.S. Forest Service (USFS).

December 1995

Virginia State Corporation Commission (SCC) issues interim order citing compelling need for additional electric capacity in the region and directs AEP to file additional information.

June 1996

USFS issues draft environmental impact statement denying AEP permission to cross federal lands. Earlier, in May 1996, the U.S. Park Service recommended denial of AEP's proposed crossing of the New River because the area was under study as a federally protected scenic river.

May 1998

Public Service Commission (PSC) of West Virginia approves construction of Wyoming-Cloverdale line.

September 1998

SCC directs AEP to study and report on an alternate routing, from Wyoming to AEP's Jacksons Ferry Station.

May 2001

SCC approves construction of the 90-mile (145-km) Wyoming-Jacksons Ferry line.

March 2002

PSC amends its 1998 order to approve new route.

December 2002

USFS issues environmental impact statement and recommends the line be allowed to cross federal lands.

December 2003

Right-of-way clearing begins, following right-of-way acquisition and design.

April 2004

Tower foundation construction begins, with first tower erected in August.

October 2005

Final tower completed. Electricity scheduled to flow by mid-2006.