IEEE Power & Energy Magazine - November/December 2016 - 43

29,895

22.3

Midwest

21,098

15.8

Nuclear

Biomass

Oil
Wind

Coal
Others

figure 2. Brazil power generation by source in 2014
(GWh and %).
november/december 2016

as
t
N

12,210, 2.1%
13,590, 2.3%
44,733, 7.6%
15,378, 2.6%
18,385, 3.1%
31,668, 5.4%
81,075, 13.7%
373,439, 63.2%

Natural Gas

or
th
e

or
th
N

figure 3. Brazil power generation by region (GWh).

A third short circuit on phase C of the Itaberá substation
bus occurred 3.5 ms after the second event. This third fault
was eliminated by the differential protection. This unusual
sequence of faults produced a very high current with high
harmonic and dc components in the neutral of the circuit's
three shunt reactors, causing their disconnection. As a consequence, the 60-Hz portion of the Itaipu power plant was
disconnected from the southeast region and left connected
to the system only through the Southern Region.
After the loss of the 765-kV bulk transmission lines,
there were numerous outages in the 500-kV system, characterizing a cascading event. As a consequence, a voltage collapse occurred in the receiving southeast system,
affecting several states. The voltage drop on the bulk
power system resulted in the outage of several power
plants that supply energy to the southeast in the states of
São Paulo and Rio de Janeiro. The outages included five
units at Itaipu 60 Hz that tripped by special protection
systems and the southern region islanded. Furthermore,
the two HVdc bipoles associated with the Itaipu 50-Hz
generation were blocked by their undervoltage protection.
It is important to stress that the disturbance propagation
did not reach the northern and northeastern regions. The
postevent analysis concluded that the faults at the Itaberá

Hydro

69,836

South

es
t

32.2

18.7

43,131

24,993

Southeast

162,292

Northeast

11.0

ut
h

14,795

North

as
t

100

ut
he

133,913

Brazil

96,449

% of Total Capacity
80,700

181,201

table 2. Brazil's installed generation capacity
by region (2014).

substation were caused by lightning and/or the reduction
of the effectiveness of the insulators due to adverse meteorological conditions.

Main Consequences of This Blackout
The number of customers affected by the 10 November
2009 blackout was around 40 million people, with a total of
24,436 MW of interrupted load. The average load restoration
time was 222 min, as shown in Table 4.

Blackout of February 4, 2011
The system was operating under normal conditions with
the northeast region importing 3,237 MW from neighboring regions. The total load in the northeast region was
8,883 MW. One of the bulk power system lines, the 500-kV
line between the Milagres and S. João do Piauí substations,
was out of service for maintenance. This disturbance can be
divided into two events.
In the first event, the disturbance started at the Luiz Gonzaga substation that has a breaker and one-half configuration. At 00:08 a.m., due to a malfunction in the substation
protection, circuit 1 of the 500-kV line from Luiz Gonzaga
to Sobradinho was disconnected. The malfunction mistakenly sensed a breaker failure at the 15D1 breaker, and thus

table 3. The transmission line mileage
by voltage level.
mi/km

% of Total EHV
Mileage (2014)

Total

78,086/125,640

100

230 kV

32,598/52,450

41.7

345 kV

6,403/10,303

8.2

440 kV

4,181/6,728

5.4

500 kV

25,270/40,659

32.4

600 kV dc

7,965/12,816

10.2

765 kV

1,667/2,683

2.1

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