Download First Trans-Rupter II Transformer Protector Installation in Brazil

TRANS-RUPTER II®
TRANSFORMER PROTECTOR
First Trans-Rupter II Transformer Protector
Installation in Brazil
Background
Meeting specifications
Brazil’s ongoing national initiative, “Luz no campo” (“Light
in the countryside”), promises to upgrade the electrical
infrastructure of rural areas, providing economic stimulus
and improved quality of life for residents. This program
requires construction of many new substations.
The utility’s specifications for transformer protective
devices are based on circuit breakers. Trans-Rupter II
Transformer Protector offers many functions of a breaker
but has been tailored specifically for transformer protection.
It thus doesn’t have—or need—the expensive features of
a general-purpose breaker. CEMIG requested a number of
modifications to the low-voltage enclosure to help TransRupter II meet the specifications, including:
h Salvador
h Cuiaba
Brasilia
a
h Goiania
BRAZIL
h
Uberlandia
h Campo
Grande
ARGENTINA
• A trip-coil monitoring circuit.
h Montes
Claros
Belo
Horizonte
h
h Vitoria
PARAGUAY
São Paulo h
h Santos
h Foz do
Iguacu
Vitoria de
Conquista
h
h
Rio de Janeiro
Curitiba h
h Florianopolis
Porto Alegre
h
URUGUAY
h Rio Grande
First Brazilian Trans-Rupter II installation located in Montes Claros.
With limited monetary resources available, one regional
electrical utility, Companhia Energética de Minas Gerais
(CEMIG), sought ways to save on the purchased and
installed costs of equipment. They turned to S&C Brasil for
suggestions.
• Additional auxiliary contacts, for use with CEMIG’s
SCADA system.
• An electrical operation counter. The peak value of
every fault current interrupted would be stored in the
coordinating digital protection relay.
• Additional remote gas-density indicator contacts.
• A loss-of-dc-voltage relay.
• A pole-unit monitoring circuit. This circuit prevents the
transformer from being energizing until all three TransRupter II pole-units have been closed and charged.
• A separate dc control-power protector.
• A space heater, convenience light, and power outlet.
S&C Brasil offered Trans-Rupter II Transformer Protector as
an alternative to the costly circuit breakers CEMIG typically
uses for transformer protection. The utility was attracted to
Trans-Rupter II’s initial cost savings, plus its no-maintenance
operating mechanism. They planned a trial Trans-Rupter II
installation at a new substation located close to Montes
Claros, one of the most economically underdeveloped areas
of Minas Gerais, where low-cost power is crucial. But there
were a few hurdles to overcome . . .
Trans-Rupter II low-voltage enclosure was modified to meet the
utility’s specifications.
S&C ELECTRIC COMPANY
Specialists in Electric Power Switching and Protection
Case Study 731-1009
October 25, 2004
New Publication ©2004
Passing the test
Besides meeting their specifications for transformer
protection devices, CEMIG required that Trans-Rupter II
pass a series of qualifying tests, including:
• A temperature-rise test, utilizing thermocouples installed
inside specially designed pole-units.
• A 5000-operation mechanical test.
• An ultraviolet radiation test, to verify that the polymersilicone insulation would hold up under the extreme
equatorial sunshine of the Brazilian highlands.
• A radio-influence voltage test.
• A lightning-impulse test.
• A pole-unit tripping simultaneity test.
S&C performed the first three tests at the Nicolas J. Conrad
Laboratory at its U.S. headquarters in Chicago, Illinois,
with representatives of CEMIG in attendance. The last three
tests were performed in Brazil. Trans-Rupter II Transformer
Protector passed CEMIG’s test requirements with flying
colors.
The results
CEMIG placed a trial order for a specially modified 138-kV
Trans-Rupter II Model EX as discussed above, with optional
motor operators for charging and closing the pole-units.
138-kV Trans-Rupter II Transformer Protector Model EX during
installation.
Installation took just one day, with another day for
completion of the control-circuit wiring connections.
Technicians from S&C Brasil supervised the installation
and provided training to CEMIG’s substation engineering
group. The Trans-Rupter II protects a 10-MVA, 138- to
13.8-kV transformer serving rural customers and small
farming communities.
CEMIG is well pleased with the performance of their trial
Trans-Rupter II. They have seven other substations planned
for the area and are considering using Trans-Rupter II for
these installations as well. CEMIG appreciated how quickly
S&C Headquarters in Chicago and S&C Brasil coordinated
testing and engineering services to accommodate the
specification requirements, and satisfactorily meet all
testing and product delivery dates.
Completed Trans-Rupter II Transformer Protector installation.