The Urban Challenge:Completing America’s Electricity Superhighway System

By John B. Howe, American Superconductor

After a long hiatus, major electric transmission projects are once again under way. Yet land use conflicts and high construction costs in our growing metropolitan areas pose barriers to the completion of an integrated “National Transmission Grid” that can connect our cities to lower-cost, more remote energy sources. Superconductor cable could soon offer an important new technology tool to help urban utilities meet this challenge.

Are America’s Cities on an Energy Collision Course?

How will the growing electricity needs of America’s 21st century cities be met? Urban power grids are under pressure from rapid population growth, a steady migration to metropolitan areas and the ongoing electrification of energy demand in our high-tech economy. Meanwhile, rising natural gas prices are forcing a shift toward more abundant alternative energy resources that tend to be remote from these centers of demand. More transmission capacity is essential, but nowhere is siting more difficult than in urban areas. Are these pressures putting our cities on an energy collision course?

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Some would argue that this challenge can be met by streamlining and federalizing the transmission siting process, using the model of the Eisenhower-era interstate highway system. Only with strong federal leadership, they contend, can ambitious infrastructure development projects with massive national economic benefits be realized. However, while certainly a great success on a continental scale, the highway program’s history of conflict and siting opposition in dense, older urban areas presents a cautionary tale.

This history suggests that urban power planners, like transportation planners before them, will face continuing pressure to explore new strategies to improve management of existing assets, and to alleviate the need for disruptive new infrastructure corridors. Yet such alternatives may not be enough to give our cities the opportunity to grow and prosper over time. Ultimately the need for stronger, more secure power networks, and the demand to conserve the urban fabric, will drive the need for new technology tools that support growth. High-capacity, compact underground superconductor cable promises a new way to build electricity “superhighways” in even the most physically constrained areas.

Origins and Development of the Interstate Highway System

Striking parallels link the development of our highway and power delivery networks. In the early 20th century, America depended primarily on railroads and ships to deliver goods, with roadways serving local delivery needs. Young Lieutenant Colonel Dwight Eisenhower experienced the pitfalls of overland transportation as he led a two-month cross-country convoy during the summer of 1919, averaging 6 mph. This experience led him to envision a modern, continental-scale system of high-speed roads, serving dual defense and commercial purposes. President Roosevelt embraced this vision in the 1930s, and signed the first Federal-Aid Highway Act in 1944. That Act failed, however, to provide a viable mechanism for funding construction. It was 12 years later that the Interstate Highway Act-the signature program of Eisenhower’s presidency-corrected this deficiency with a modest gasoline tax.

This program quickly achieved dramatic success at modest cost. A 1982 Government Accounting Office (GAO) study found that more than 38,000 miles of high-capacity, limited-access highway, linking nearly all major cities, had been built at a cost (in 1979 dollars) of roughly $4 million per mile. This early success owed much to demographics. America’s total population was barely half today’s level, and road projects in remote, lightly populated farmland, forest, plains or desert provoked little opposition. Smaller and newer cities embraced them as engines of growth.

Meanwhile, highway construction through older, denser cities began to provoke a backlash, even in the otherwise-quiescent 1950s. The first “Freeway Revolt” arose in response to a 1956 plan to blanket San Francisco with a checkerboard of limited-access highways. Citizen opposition prevailed, and the revolt spread to older cities nationwide. In 1972, after a bitter decade-long battle, Massachusetts was forced to suspend all new highway construction within the beltway surrounding Boston. Older urban fabric was preserved at the cost of chronic traffic congestion.

Elsewhere, protests in many cities-including Atlanta, Baltimore, Miami, Milwaukee, New York, New Orleans, Portland and Washington, DC, to name a few-led to the cancellation or costly rerouting and redesign of ambitious highway projects. The GAO’s 1982 study projected that the final 5 percent of the interstate system-much of it in urban areas-would cost nearly eight times as much in real terms as the portion already completed. In fact, the unique conditions of urban construction forced some project costs far higher before the system was declared complete in 1991. Boston’s recently completed “Big Dig” yielded eight miles of highway at an egregious cost (in 2000 dollars) of $14 billion.

More transmission capacity is essential, but nowhere is siting more difficult than in urban areas.
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To stave off transportation gridlock, urban planners have been forced to explore a variety of creative strategies to reduce or time-shift demand. These have ranged from toll roads and time-varying tolls, to HOV (high-occupancy vehicle) and reconfigurable travel lanes, to mass transit and other enhancements such as bikeways-and even telecommuting incentives. Where they have proceeded, urban highway projects have often adopted costly mitigation measures to win acceptance. These range from tunnels and surface decks to below-grade construction, sound barriers, and other aesthetic enhancements beyond basic utilitarian designs.

Back to the Future: The Evolving Vision of a “National Transmission Grid”

The evolution of America’s power transmission network is remarkably analogous to the interstate highway history. Through the 1980s, America’s utilities designed their systems to support the local production and delivery of power. Major regional grid projects were typically built in areas with large-scale nuclear and hydropower facilities. Following on the success of restructuring efforts in the natural gas and telecom industries, the Energy Policy Act of 1992 (EPAct ’92) sought to graft a wholesale competitive market structure onto a physically inadequate network. These reforms floundered in many regions. Many blamed EPAct ’92 for causing confusion and falling grid investment, as the act authorized open access without clarifying how to pay for grid upgrades.

The costly disruptions that followed-including price spikes, blackouts and mounting congestion-prompted the same kind of epiphany experienced by Colonel Eisenhower on his grueling 1919 convoy. The early years of this decade saw renewed calls for a “National Transmission Grid” and, finally, legislative action. The Energy Policy Act of 2005 (EPAct ’05) made grid modernization a centerpiece. Correcting many of the deficiencies of EPAct ’92, the new law mandated industry reliability standards, directed FERC to develop stronger grid investment incentives, and gave the agency backstop siting authority to address “national interest bottlenecks” identified by the U.S. Department of Energy (DOE). After a long hiatus, major new long-distance high-voltage interregional power line projects are proceeding. Two prominent examples-the four-state Frontier line in the west and American Electric Power’s I-765 line in the east, consciously modeled on the Interstate Highway System-promise to meet critical national needs by bringing large amounts of low-cost, remote energy to the nation’s coastal markets.

Meeting the Special Needs of Cities

While major new long-distance interstate lines have received fresh impetus from EPAct ’05, the challenge remains: How will rising power flows be integrated into the delivery networks of our growing and spreading cities, where siting obstacles are most acute? Steady urban expansion drives the need for the electrical equivalent of off-ramps, bypasses, loops and radial highways. Yet this same growth will make land and construction only more costly. Today, one-third of Americans live and work within two dozen metropolitan “hot spots” that occupy well under 1 percent of the nation’s land mass. Energy density and land values in these cities can be literally thousands of times higher than in rural regions.

Over the past decade, with siting opposition on the rise, power system planners and policymakers have focused on a wide range of strategies to avoid or defer the need for new power line corridors. These non-grid options have included innovative pricing, energy efficiency, backup and distributed generation. Such approaches can remove some of the “traffic” from the electricity highway. Yet there is a strong, enduring link over time between economic growth and electric power consumption. While technology trends are making Americans more energy-efficient and productive, they are simultaneously making us much more electricity-intensive! In short, if our cities are to remain vibrant, it is essential that our urban power grids have the tools and technologies to grow.

What if large amounts of transmission could be added to urban power networks without the physical space requirements and disruption of conventional lines? It is this vision that drives interest in high-capacity, high temperature superconductor (HTS) power cable. Made from wires that carry over 150 times more current than copper with negligible electrical losses, HTS cable offers much higher capacity than conventional underground cables in any given voltage class. This new tool could broaden planning options: Utilities could increase their delivery capacity at native transmission voltage levels, or gain faster project acceptance by solving transmission-level problems with distribution-voltage equipment. The physical traits of superconductors will make such cables controllable and thermally independent of the surrounding environment-an important advantage that has precluded use of conventional underground copper cables in many cities due to soil and climate conditions. These traits will enable low-cost, ultracompact installations in a wide range of available rights-of-way, including rail lines, highways, existing utility corridors and recreational paths-minimizing costly conflicts with existing infrastructure.

Superconductor cable technology has made continuous strides toward full-scale commercialization over the past decade. Three diverse new demonstration projects are slated to begin operations in the United States during the coming year. In June 2006, a 350-meter 34-kV “triplex” distribution cable will commence operations in the National Grid system in Albany, N.Y., developed by a team consisting of SuperPower, Sumitomo Electric and BOC. In August, a 200-meter 13.4-kV “triaxial” distribution cable will be demonstrated at a substation on the AEP system outside Columbus, developed by a team consisting of Ultera, American Superconductor and Praxair. In early 2007, a 600-meter 138-kV transmission cable system will begin operations in the Long Island Power Authority’s grid in the town of Holbrook, N.Y., developed by a team that includes American Superconductor, Nexans and Air Liquide. All have been developed under cost-sharing agreements with the U.S. Department of Energy. Worldwide, a dozen HTS cable demonstration projects are under way in Mexico, Germany, Japan, Korea and China. With sufficient demonstration experience and ongoing progress in such areas as dielectrics and refrigeration systems, this cable technology could become available on a fully commercial basis by the end of this decade. This advance would offer urban utilities a new approach to some of their most challenging power delivery problems.


In the realm of energy, electrification is our nation’s history and destiny. Electricity feeds 40 percent of our energy end-use and powers more than 80 percent of our economic growth. It has steadily spread from lighting and manufacturing to air conditioning, computerization and the Internet. If the promising concept of the highly efficient “plug-in hybrid” automobile takes hold, the grid could soon support personal transportation as well! As our backbone energy infrastructure, the grid is critical to our economy and security; it is not surprising, then, to hear calls for a national transmission grid modeled on the nation’s highway system, with a prominent federal siting role.

However, as occurred in the era of highway expansion, many of the most troublesome siting problems will persist in and around the metropolitan areas where more Americans are choosing to live and work, especially the dense, older urban areas where construction costs are highest. Strategies that manage grid congestion can help utilities to defer upgrades in these areas. However, to enable these areas to grow and prevent electricity consumers from being “stuck in traffic,” these areas will require the equivalents of ring roads, spurs and off-ramps. Given the high construction and land costs of urban areas, these elements must be more compact and lower-profile to gain community acceptance and assure timely completion. High-capacity superconductor cable offers the promise of a solution to this problem. As cable system engineering issues are resolved and pending demonstration projects establish a reliability record, this technology could soon play a major role in realizing the vision of an integrated, high-performance national transmission grid-a true electricity superhighway system.

John Howe is vice president of electric industry affairs for American Superconductor and chairman of the Coalition for the Commercial Application of Superconductors, a national trade association. He was formerly Chairman of the Massachusetts Department of Public Utilities.


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Getting Equipped

Power system test equipment is essential to the continuing safe operation of T&D equipment. In this issue’s “Getting Equipped” feature we take a look at a few of the latest product introductions in the field of power system test equipment.

Doble M5200 SFRA

The M5200 SFRA Sweep Frequency Response Analyzer from Doble Engineering is the newest addition to the company’s line of diagnostic instruments. The M5200, which utilizes an external PC, is designed to detect mechanical problems in power transformers.

Power transformers are subject to many kinds of physical damage that can be nearly impossible to detect. Once a transformer has been damaged, even if only slightly, the ability to withstand further mechanical stress is reduced. Doble’s SFRA technology provides a view inside the transformer without detanking. With Doble’s SFRA technology, users can identify core and coil structural defects early, and avoid unscheduled outages, downtime or internal inspections.

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The Windows-based software of the M5200 SFRA includes analysis tools to help users identify any differences between two SFRA measurements. The two traces are displayed on a graph, while the differences between the two are plotted in dB values on separate graphs. Users can control the colors so the “difference chart” is red, yellow or green depending on the magnitude of differences between traces. This helps identify differences between data sets. The data is stored in a simple format, and can be accessed through standard spreadsheet applications and shared with other users through the Doble SFRA Forum.

Omicron CT Analyzer

Omicron’s CT Analyzer is a multifunctional instrument designed to perform excitation, ratio, polarity and winding resistance tests on current transformers (CTs) as well as burden-impedance measurement.

The equipment provides automatic testing and calibration for all types of low leakage flux current transformers both on-site in the power system as well in the controlled environment of CT and switchgear manufacturers.

The CT Analyzer allows an automatic assessment of test results clearly indicating whether the parameters of the CT under test match its specification. It is also applicable to the testing of specialized CTs such as TPS, TPX, TPY and TPZ.

Omicron CT Analyzer
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With the CT Analyzer, current transformer testing can be carried out to an extremely high level of accuracy, making it ideal for calibration and verification, not only for protection CTs but also for metering CTs of class 0.2.

The CT Analyzer provides a wide range of test and measurement possibilities, including: burden measurement; CT winding resistance measurement; CT excitation characteristic recording; CT transient behavior measurement; CT ratio measurement with consideration of connected burden; CT phase and polarity measurement; determination of accuracy limiting factor, instrument security factor, secondary time constant, remanence factor, knee point voltage/current, class, saturated and non saturated inductance; and assessment according to defined standards: IEC60044-1, IEC60044-6, IEEE C57.13-1993.

The weight (less than 17 pounds) of the CT Analyzer hardware makes it particularly beneficial for on-site testing.

Megger TTR25

Designed for simple operation, Megger’s new TTR25 automatic transformer turns ratio set is ideal for single- and three-phase transformer testing. The instrument is able to accurately measure a high turns ratio of 20,000:1 in less than five seconds and quickly locate a range of problems, including problems in transformer windings and magnetic core circuits.

Megger TTR25
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In addition to measuring small ratio changes, the unit measures excitation current and normal and reverse polarity of single-phase transformers. It is also useful for measuring both tapped and potential and current transformers. As a result of its accuracy (+- 0.1 percent), the tester effectively reduces the need for additional equipment.

Its design, including a shock-resistant case, makes the TTR25 well-suited for most environments. The battery-operated unit comes with a single-button operation feature and a quick-start guide on the front panel. It is lightweight (2.8 pounds including leads), small enough to be held in one hand and able to provide up to 12 full hours of field operation.

Well-suited for testing in substations, transformer-manufacturing environments and meter shops, the unit features a high-contrast backlit LCD screen that is visible in either bright or ambient light. The TTR25 needs no additional software and comes with six operator-selectable languages.

Dranetz-BMI AnswerModules

Dranetz-BMI has added AnswerModules to its line of handheld power monitoring instruments. AnswerModules, developed originally for Dranetz-BMI’s Signature System continuous monitoring system, are proprietary algorithms that convert raw power quality event data into precise answers to determine the source and cause of disturbances. The modules enable users to save time and improve accuracy when troubleshooting power quality problems.

Three AnswerModules-the sag directivity, power factor capacitor switch and motor quality annunciator AnswerModules-are now provided at no extra cost with the purchase of the PowerXplorer PX5, PowerXplorer PX5-400 and PowerGuide 4400 instruments.

Dranetz-BMI PowerXplorer PX5
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The most common type of power quality disturbances is the voltage sag. The Voltage Sag Directivity AnswerModule automatically identifies a voltage sag event and determines the direction of its location relative to the monitoring point. Knowing the location of the sag is the starting point to resolving the problem and protecting operations.

Power factor correction capacitors provide voltage support and correct power factor on power distribution systems. While capacitor switching is common, it can cause transients that disrupt manufacturing machinery, adjustable speed drives and process controls. The Cap Switching AnswerModule identifies and characterizes the disturbance and its direction, relative to the monitoring point for rapid decision-making and mitigation.

There are various electrical parameters that either adversely affect the health of an electrical motor, or are an indication of the health of the motor. The Dranetz-BMI motor quality annunicator panel displays those parameters in a single color-coded screen. The key parameters are voltage, current, unbalance, power factor, voltage THD, current THD, negative sequencing component, and horsepower. The instrument also provides a single parameter within the AnswerModule panel, called Derating Factor, a cumulative indicator of these adverse parameters. ࢝®à¢®