"Lessons of the Blackout," Feature Article, August 2004

lessons of the blackout

Plenty has changed since the lights went out last year, but there is more work left to do.

by James Fama

The North American electric system is one of the great engineering achievements of the past century. Today, more than 3,000 electric utilities deliver almost 4 billion kilowatt-hours of electricity over 160,000 miles of high-voltage transmission lines to more than 280 million customers nationwide. Ensuring that the system delivers a reliable electricity supply has been paramount since Thomas Alva Edison's Pearl Street Station in lower Manhattan began powering a handful of his newly developed incandescent light bulbs on September 4, 1882.

The U.S.-Canadian blackout, a year ago this month, demonstrated the need for new reliability measures. In the past year, the power industry has come together to put many safeguards in place. Their actions will improve the grid's reliability. But to ensure that the grid can keep up with the continually growing demands placed upon it, we need more.

The Edison Electric Institute, the trade organization for the investor-owned utilities that generate about 70 percent of the electricity consumed in the United States, is taking reliability to Congress. We believe the system needs federal legislation to enforce operating standards that, until now, have been voluntary, and to lower some of the obstacles to much-needed development of power transmission lines.

Only a combination of reliability actions and an expanded infrastructure can ensure that America's electric system will be able to meet the demands it will face in the 21st century.

In early April, the U.S.-Canada Power System Outage Task Force, appointed by the heads of state of both countries, issued its "Final Report on the August 14, 2003 Blackout in the United States and Canada: Causes and Recommendations." The text is available online at http://www.nerc.com/~filez/blackout.html. The group wrote that, to prevent blackouts of this scale from happening again, the grid needs clearer reliability standards with mandatory enforcement and more oversight independent of influence by interested parties.

Earlier this year, with industry support, the voluntary organization that oversees bulk electrical transmission on the continent—The North American Electricity Reliability Council, or NERC—began to implement measures to address many of the recommendations later detailed in the report. Key among them was reformatting and clarifying its reliability standards.

Operating policies and planning standards are already in place, but published in a number of separate documents. Most of the new standards are scheduled to be completed in December, and adoption by the NERC board is expected in February 2005.

These mandatory reliability standards will be aimed at achieving seven NERC goals.

To balance power generation and demand continuously: Production by generators must be scheduled and dispatched to meet constantly changing demands, and adjusted continuously. Failure to do so causes the frequency of an ac power system, nominally 60 Hz, to increase when generation exceeds demand or decrease when generation is less than demand. Random, small variations in frequency are normal.

However, large deviations in frequency can cause the rotational speed of generators to fluctuate, leading to vibrations that can damage turbine blades and other equipment. Extreme low frequencies can trigger automatic under-frequency "load shedding," which takes blocks of customers off-line to prevent a total collapse of the electric system.

To balance reactive power supply and demand to maintain scheduled voltages: Reactive power sources, such as capacitor banks and generators, which are maintained for the explicit purpose of insuring continuous, steady voltage on transmission networks, must be adjusted during the day to maintain voltages within a secure range for all system parts—stations, transmission lines, and customer equipment.

ABB supplied a DC transmission link, shown under construction, to connect Long Island and Connecticut.

Most generators have automatic voltage regulators that adjust reactive power output to maintain voltages at scheduled levels. Low voltage in transmission lines can cause electric system instability or collapse, and on distribution lines can cause damage to motors and the failure of electronic equipment. High voltages can exceed the insulation capabilities of equipment and cause dangerous electric arcs.

To monitor flows over transmission lines and other facilities to ensure that thermal limits are not exceeded: All lines, transformers, and other electrical equipment are heated by the current flowing through them. Line flows must be limited to prevent equipment from overheating. Most transmission lines, transformers, and other current-carrying devices are monitored continuously to ensure that they do not become overloaded or violate other operating limits. Multiple ratings are typically used, one for normal conditions and a higher rating for emergencies. The primary means of limiting the flow of power on transmission lines is to adjust selectively the output of generators.

To keep the system in a stable condition: Because the electric system is interconnected and dynamic, electrical stability limits must be observed. Stability problems can develop very quickly—in just a few cycles,—or more slowly, over seconds or minutes. The main concern is to ensure that generation dispatch and the resulting power flows and voltages are such that the system is stable at all times.

To operate the system so it remains in a reliable condition: The central organizing principle of electricity reliability management is to plan for the unexpected. The unique characteristics of electricity mean that when they arise, problems, such as the loss of a key generator or transmission facility, can spread and escalate very quickly if proper safeguards are not in place. Through years of experience, the industry has developed a network of defensive strategies for maintaining reliability, based on the assumption that equipment can and will fail unexpectedly on occasion.

To plan, design, and maintain the system to remain reliable: Reliable power system operation requires far more than monitoring and controlling the system in real-time. Thorough planning, design, maintenance, and analysis are required to ensure that the system can be operated reliably and within safe limits.

Short-term planning addresses day-ahead and week-ahead operations planning; long-term planning focuses on providing adequate generation resources and transmission capacity to ensure that in the future, the system will be able to withstand severe contingencies without experiencing widespread, uncontrolled cascading outages.

To prepare for emergencies: System operators are required to take steps to plan and operate a reliable power system, but emergencies can still occur. Stress from external factors such as severe weather, operator error, or equipment failures can exceed planning, design, or operating criteria. For these rare events, the operating entity will be required to have procedures covering a credible range of emergency scenarios.

In addition to compliance with these mandatory reliability standards, NERC has proposed a number of other measures. For instance, NERC staff has conducted readiness audits of more than 20 of the largest control areas in North America, representing the majority of the continent's customers. This series of audits will assess an energy provider's readiness to operate the system in a reliable manner.

NERC 's auditors, assisted by staff from the Federal Energy Regulatory Commission, will assess each control area's capability to comply with existing policies and operator requirements. Audits, which will be conducted on a repeating three-year cycle, include assessments of a control area's personnel, training and certification, communications systems, and planning and modeling tools.

Regional reliability councils are required to report potential violations for investigation and analysis, and to submit quarterly compliance reports. Also, the NERC board has requested a recommendation from the industry by December 31 that will address performance monitoring and stronger disturbance analysis functions, such as investigating line failures and their causes.

Although NERC considers its standards mandatory, the council has no enforcement authority. It has, however, approved a set of formal guidelines for reporting and disclosure of its audits and policy violations, so that after due process the council can publicly identify any entity that fails to comply.

The council has begun developing a standard for vegetation, which can interfere with power lines. A new compliance template proposes to require all transmission line owners to certify annually that they have vegetation management plans and have carried them out. NERC already requires reporting of vegetation-related line outages. It will do this while recognizing regional differences and the states' critical role in right-of-way management.

NERC will review its operator training and certification programs, as a preparation to developing standards over the next year that will specify training requirements. It has required all operators to complete five days of supplemental training on emergency procedures by June 30.

A Siemens convertible static compensator in Marcy, N.Y., switches power between congested and underused lines of the New York Power Authority.

Reactive power and voltage control were two critical aspects of the blackout, so NERC will require reviews and, if necessary, replacements of relay devices on the grid. The council will revise operating policies to clarify the roles of entities with direct operational controls of the grid.

During the next year NERC will review a broad range of system design, planning, data gathering, and management, then make substantive recommendations to its board.

EEI's board of directors supports the council's interim measures. But EEI argues the initiatives are only part of the answer and is proposing legislative and regulatory policy action to bolster the grid in the years ahead. Electric transmission infrastructure must be maintained and expanded to meet the increasing demands being placed upon it. Investments, however, are not keeping pace with these growing needs.

Billions of dollars are being spent annually on transmission facilities. But, most of the new lines serve local load and connects new generation to the grid. Long-distance, high-voltage wires are needed to strengthen regional electricity markets.

According to NERC, the volume of transmission transactions has increased by 400 percent in the last four years. Since the latter half of the 1990s, higher voltage line-miles have been growing at only 0.3 percent a year, while lower voltage line-miles were growing at 3.5 percent. The number of transactions that could not be completed because of congestion on transmission lines increased to almost 1,500 in 2002, compared with 300 uncompleted transactions in 1998.

Several factors have accounted for the drop in transmission investment. Difficulties in siting transmission lines are key among them. Individual states currently have sole jurisdiction over where to build new transmission lines. And many state siting statutes focus on evaluating only state needs, thus preventing formal consideration of the evolving regional nature of the grid and its role as a critical feature of wholesale markets.

Resolving these siting issues will certainly remove significant obstacles to greater investment in high-voltage transmission infrastructure. But energy legislation also must provide direct incentives for investment. Pricing incentives are needed.

The Edison Electric Institute is not alone in its stand. FERC, which regulates interstate transmission rates, has proposed incentive pricing to help promote expansion of power lines.

The commission also has advocated federal legislation allowing for federal intervention under special circumstances involving the siting of interstate transmission lines.

As the 21st century begins, America's electric companies are committed to actions that will improve the grid. We have worked to draft and adopt mandatory reliability standards. And we are encouraging Congress to pass a comprehensive energy bill that spurs investment in needed transmission infrastructure. Together, these steps will help to ensure that the country enjoys the world's most reliable and affordable electricity supply for another 100 years.

James Fama is the executive director of the Energy Delivery Group of the Edison Electric Institute.