- 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
- 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
- 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
- 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.