The Great Northeast
Blackout of 1965

Central Maine Power Company

On November 9, 1965, the largest blackout in history occurred. The northeast power system broke up 4 seconds after the initial disturbance, and 30 million people were without electricity for as long as 13 hours. Later that day, President Lyndon Johnson wrote to the chairman of the Federal Power Commission:
"Today's failure is a dramatic reminder of the importance of the uninterrupted flow of power to the health, safety, and well being of our citizens and the defense of our country.
"This failure should be immediately and carefully investigated in order to prevent a recurrence.
"You are therefore directed to launch a thorough study of the cause of this failure. I am putting at your disposal full resources of the federal government and directing the Federal Bureau of Investigation, the Department of Defense and other agencies to support you in any way possible. You are to call upon the top experts in our nation in conducting the investigation.
"A report is expected at the earliest possible moment as to the causes of the failure and the steps you recommend to be taken to prevent a recurrence."
Lyndon B. Johnson
The Event
The Great Northeast Blackout of November 9, 1965 began at 5:16 p.m., near the end of an otherwise typical work day.
The event started at the Ontario - New York border, near Niagara Falls.
A single transmission line from the Niagara generating station tripped (opened).
Within 2.5 seconds, five other transmission lines became overloaded and tripped, isolating 1,800 MW of generation at Niagara Station.
After their isolation, the generators became unstable and tripped off-line.
The northeast power system became unstable and separated into isolated power systems (islands) within 4 seconds.
Outages and islanding occurred throughout New York, Ontario, most of New England, and parts of New Jersey and Pennsylvania.
Most islands went black within 5 minutes, due to imbalances between generation and load (generator overspeed/underspeed tripping).
The massive blackout left 30 million people without electricity for as long as 13 hours.
This was "the big one" and it all started with the operation of a simple overcurrent relay on a transmission line. The design and operation of electric utility systems changed after that, due to the lessons that were learned from this event.
Areas of Separation at 5:17 PM
November 9, 1965
Orange: Ontario Hydro System
Yellow: St. Lawrence - Oswego
Blue: Western New York
Red: Eastern New York - New England
Green: Maine and part of New Hampshire
The green area did not lose power during the blackout.
Regional Reliability Councils
The regional reliability councils were formed in the wake of the 1965 Northeast blackout:
Northeast Power Coordinating Council (NPCC) was formed in January, 1966.
Federal Power Commission's blackout report was issued June, 1967.
National Electric Reliability Council, now North American Electric Reliability Council, (NERC) was formed in June, 1968.
NPCC, our regional reliability council, was the first one. Today, there are ten regional reliability councils. (Florida is the newest, creating its own in 1996, after having been in the Southeastern Electric Reliability Council). NERC is an association of the regional reliability councils. Although the organization and workings of each regional reliability council are different, they have a common factor - each one has its own criteria, which establish minimum standards. An important aspect of assuring reliability is sharing information necessary for system analysis, and coordination of system design and operation.
Then and Today
Compared to today's system, the 1965 system was much less networked. Some areas had strong interconnections while others were weak. In fact, the State of Maine survived the 1965 blackout because of its weak ties to the rest of New England, which tripped.
System impedance (electrical "distance") between Bangor, Maine and Portland, Maine is about 8 times less today than it was in 1965. In terms of electrical distance, Bangor is as close to Tennessee or Michigan today, as it was to Portland in 1965. This is approximate, and based on broad estimates. However, it illustrates the interdependency of today's system, compared to 1965. We must be much more careful today if we are to avoid a widespread disturbance, simply because of the close ties we have with other power systems.
Today's Power System
New England now has a well-developed 345 kV network, with 345 kV ties and High Voltage Direct Current (HVDC) ties to neighbors.
In northeast North America, we design to what we call "Normal Contingencies", and we use redundant, independent protection systems where required. We test system resiliency with "Extreme Contingencies". We monitor what we call Special Protection Systems (SPSs), which are fast-acting relay, communication, and control systems for generator, line, load, or other cross -tripping. There are more devices with fast controls today.
The North American Interconnected Systems today are four major independent systems, or networks:
Eastern Interconnected Network (east of the Rockies). This system is all but the ERCOT and WSCC reliability councils, and the Quebec portion of the NPCC reliability council.
Quebec. This system is part of the NPCC reliability council.
Texas. This system is the ERCOT reliability council.
Western Interconnected Network (west of the Rockies). This system is the WSCC reliability council.
These four systems are asynchronous, tied together only by DC interconnections. These systems include continental Canada, the contiguous United States, and northern Baja Mexico. Other systems are: Alaska, Mexico, and Labrador. These systems are illustrated in the following NERC map of reliability councils.
The eastern interconnected network is, arguably, the largest machine in the world. The network has thousands of sources, hundreds of millions of miles of lines, and over a billion individual loads. Despite its complexity, this network operates in continuous synchronism as a single system. The power systems are so well connected, a single disturbance can be detected thousands of miles away.
This page is adapted from a presentation made by Dave Conroy of CMP to the Maine Section IEEE. The presentation was made on the eve of the 30th anniversary of the blackout.




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