IEEE Power & Energy Magazine - January/February 2022 - 47

restrict power exchanges between the north/northeast and
the southeast systems in case there is a loss of any circuit.
Exchange limits used for hydrothermal scheduling are
frequently updated, and a real-time security assessment is
used to update limits dynamically during real-time operations.
The export capacity limits between the areas consider
the N - 1 security criteria, and, importantly, this
includes the preparation for possible wildfires along
the path/route of the interconnections.
Relevant Events
Next, we enumerate a few relevant events that demonstrate
the impact of wildfires on the Brazilian power system.
✔ In August 2020, wildfires in the state of Rio de Janeiro
caused outages in four transmission lines of the concessionaire
FURNAS. There were, nonetheless, no electricity
supply interruptions to the final consumer.
✔ CTEEP, another transmission concessionaire, announced
that it recorded approximately 133 wildfires
in the neighborhood of its transmission lines from January
to December 2020. This represented an increase
of about 400% compared to the previous year. Among
the cities more impacted were those in the interior of
the state of São Paulo (Figure 11). Yet, CTEEP is one
of the transmission utilities with the best asset availability
levels in Brazil.
✔ In May 2019, wildfires affected the distribution lines
in the Brazilian state of Mato Grosso do Sul. According
to the local distribution utility, wildfires resulted
in more than 160 h of supply interruption in 75 of the
77 municipalities in the state. Firefighters explained
that the most frequent cause of fire outbreaks was inefficient
vegetation management, including garbage
and wood in hot, dry weather, and people who used
fire to clear lands and pastures.
✔ The year 2017 featured a severe dry season in several
regions of the country. On 10 September, there were
21 occurrences of transmission
line outages due
to wildfires, none of these
leading to load shedding.
The most critical outages
affected the north-northeast
intertie: the 500-kV
t ransmission lines Imperatriz-Presidente
Dutra
C2, Imperatriz-Presidente
Dutra C1, and Tucuruí-
Marabá. The performance
of the system without load
shedding was only possible
because the system operator
took several preventive
measures, such as reducing
loading on the possibly afjanuary/february
2022
fected transmission lines through redispatching of
generating units.
✔ On 30 August 2016, an outage in a 500-kV transmission
line in the Tocantins region (northern Brazil)
caused frequency oscillations and deeply affected the
supply of electricity in the north and northeast regions
of the country. According to the system operator, the
problem was caused by wildfires near the transmission
line in question (Figure 12). Load shedding exceeded
3 GW and affected 13 states of Brazil, impacting
15 distribution companies and four deregulated
large consumers. The system was entirely restored in
approximately 2 h.
✔ On 28 August 2013, wildfires resulted in a blackout
in Brazil with two successive transmission line outages.
At the time of the outages, there was a substantial
transfer of power from the southeast to the northeast
85
87
89
91
93
95
97
99
157
142
107 110
97
92%
89%
88%
90% 90%
20
40
60
80
Robustness Index
Transmission Line Length
figure 10. The evolution of the robustness index of the
Brazilian basic grid.
119 124 129 133
95%
94%
94% 94%
100
120
140
160
180
(a)
(b)
figure 11. (a) A wildfire under a transmission line in the Ribeirão Preto region (São
Paulo state). (b) A fire near a transmission line in Bauru (São Paulo state). (Source:
CTEEP; used with permission.)
ieee power & energy magazine
47
Robustness Index (%)
2012
2013
2014
2015
2016
2017
2018
2019
2020
Transmission Line Length 1,000 km
IEEE Power & Energy Magazine - January/February 2022

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