IEEE Power & Energy Magazine - November/December 2016 - 53

By Eric H. Allen, James Ingleson, Robert
Orndorff, Brian Starling, and M. Kyle Thomas

POWER SYSTEM DISPATCHERS THROugHOuT THE EASTERn InTERCOnnECTIOn (EI)
of the united States regularly observe unusual frequency movements during the Super Bowl championship game of American football. While these movements have not been a threat to security to
date, they are large enough to warrant explanation. We have found the explanation for these frequency
movements through load and frequency monitoring, together with careful observation. Two mechanisms are at work. First, television viewers defer load-producing activities during periods of high
interest and then carry out these activities during periods of lower interest. Second, changes in the
brightness of a televised image result in appreciable changes in the load of television sets. During the
Super Bowl, there is an unusually large number of televisions all displaying the same programming
and an unusually large number of television viewers whose activities are synchronized to this programming. The outstanding example of the aggregated impact of changes in television image brightness occurred following a partial power outage at the Superdome stadium during Super Bowl XLVII
in new Orleans on 3 February 2013.

Terminology
We will use millihertz, abbreviated mHz, for small changes in frequency, which conforms to standard
SI practice. Times are in Eastern Standard Time (EST) and 24-hour format. Following national Football League practice, each annual game is identified by its Roman numeral. For example, Super Bowl
XLVII was played in 2013. The exception is Super Bowl 50 played in 2016.

Background
It is well known that sudden frequency changes are caused by sudden changes in the generation-load
balance. A large generator tripping offline will result in a noticeable drop in system frequency due
to disruption of this balance. Equilibrium will be established at a
lower frequency due to turbine-governor action and the frequency
sensitivity of some load. In the same way, a sudden loss of load
will cause a rise in system frequency. In a minute or more, secondary frequency control will act to restore frequency to schedule,
typically 60 Hz.
A large number of frequency disturbances occur each year
on the EI during the Super Bowl. There is no other comparable
period of frequency disruption that occurs on a regular basis. For the 2013 game, Super Bowl
XLVII, monitoring was put in place in an attempt to determine the cause of the frequency disturbances, and this monitoring continued through Super Bowl 50 in 2016. Based on past observations
of frequency during the game, it is apparent that there are synchronized activities affecting system
load. Careful monitoring of events during the game, along with monitoring of key load classes,
has provided the data necessary to identify the phenomena causing these frequency disturbances.

It's More Than Just
What's on the Field

Discussion of Monitoring Provisions
For many years, system operators and engineers have observed sudden rises and drops in system frequency during the annual Super Bowl. These sudden frequency changes are very similar to the frequency changes observed during known loss of load or loss of generation events. It follows that there
must be sudden significant changes of load occurring during the game. Therefore, starting with Super
Bowl XLVII, we monitored specific classes of load that were considered likely to show such changes
during the game. We also had access to load data from Dominion Virginia Power sampled at six readings
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