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TRANSCRIPT
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PS3-1
High Voltage Hybrid & Compact Relocable Switchgear: New Design of
Equipment for Multiple Use in Construction, Maintenance and Emergency
EBP ENÉAS BITTENCOUNT PINTO, GF GLAUCO FALCÃO, DR DOUGLAS
RODRIGUES, PU PABLO UMETSU
CPFL ENERGIA, ABB LTDA.
BRAZIL
SUMMARY This work presents the result of the joint development of the engineering areas of CPFL Energia
and ABB Ltda., to design an equipment that would gather a minimum of functionalities required
in conventional Air Insulated Substations, for transmission line bays, Power transformers
connections, capacitor bank connections and bus bar interconnections, operating up to 145 kV
voltage.
In addition, the equipment was designed to be transported between different points of the electrical
system, because CPFL's idea was to use it as a temporary bay for switching and protection at a
substation expansion site, where a second power transformer would be installed. Then, after
completion of the work, the equipment would be sent to a similar one, or applied in a different
place in scheduled maintenance tasks of the conventional equipment of these bays or, also, in
emergency situations, when there were defects or failures in such equipment.
For transportation to different locations, using the roads, highways and even the streets within the
cities, it is expected that the solution would consider the use of a trailer, or semi-trailer, drawn by
mechanical horses commonly found on the market. However, it is also important to properly
position the new equipment in the correct spaces next to it bays at the substation where the
functionalities will be replaced, as indicated above.
Besides, it was also considered the possibility of allocating the new equipment under transmission
line bays, in the servitude passage range of the line, predictably next to towers or support posts or
anchorage, in points where the line can be sectioned to provisionally implement operation
functionalities, protection, sectioning and even current measurement, even in variants of lines
under construction or emergency situations.
As there are many solutions built in terms of electromechanical arrangements in substations and
lines that will be objects of the use herein conceived, this does not make small the challenge of
proper and safe positioning of the new equipment, since its installation will require the
implantation of a variant of bus bars phases not less safer, so that interim connections can be made
for each use.
However, considering that the technological evolution has allowed to design and build electrical
equipment increasingly compact, robust and functional, as well as associated in unique armoured
modules with dimensions and weights allied to the improvement in the reliability and availability
of its functions, the concept adopted was one of hybrid switchgear module with SF6 gas
insulation attached to a rigid skid platform that could be simultaneously hoisted for a trailer or
semi-trailer by road and dragged, when on the substation ground or line, for the best position
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between gantry and supporting structures of the existing equipment, because it has a smooth and
ready-made lower surface for that.
Then, from a technical specification of CPFL with the above requirements, ABB designed the new
equipment based on its already successful compact hybrid module PASS M0, with rated voltage
145 kV, nominal current 2500 A and containing the Circuit breaker functions (including a fast
reclosing cycle, typical for transmission lines), a disconnector with integrated earthling switch and
bushing type current transformers (for protection and measurement services), with the whole set
meeting the requirements of technical standardization IEC 62271-205: 2008 - Compact switchgear
assemblies for rated voltages above 52 kV - and the requirements of IEEE 693-2005 -
Recommended Practice for Seismic Design of Substations.
KEYWORDS
High Voltage Switchgear & Apparatus
Engineering solutions
Electrical System Expansion Plan
Enéas Bittencourt Pinto <[email protected]>
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INTRODUÇÃO Utilities and licensees of public electricity generation, transmission and distribution services have
been in existence for many decades, even over a century, since the general use of electricity was
conceived for the various activities of human societies in all their aspects, around the world.
The continuity of these services has long been maximized, given the enormous scientific and
technological advance in all areas of knowledge and its application, which allowed and
accompanied the great population growth, which, in turn, has demanded the expansion of
electrical systems, permanently.
However, technical solutions in all areas depend on their physical components being constantly
supervised, controlled, maintained and even replaced, so that no unacceptable interruptions occur,
or that severely compromise the proper functioning of these various activities and tasks performed
by the For companies.
It is not a small challenge, then, the procedures, staffing, and tooling that energy companies need
to use to keep electrical systems in proper operation, even when it needs to be expanded and
interfered with to solve failures, defects and occurrences that usually arise, given the age, state of
conservation and the conditions to which they are exposed, especially climatic, environmental and
interaction with the human population itself.
Power distributors are the link between the companies that generate and transmit almost all
electricity and the consumers who use it. However, in terms of physical and geographical
coverage, in order to bring energy to users spread throughout the territory, the former usually have
unique challenges in order to have an infrastructure that is efficient and cost-effective. Moreover,
in this, trained teams, standardized tasks and available tooling make a lot of difference in results.
The object of this article is inserted in this last premise, since it shows the innovation that can be
achieved, and apply, in the continuous improvement of the activities, with gains in productivity
and value added to the company. In this, it is fundamental the partnership with the market
developers manufactures and commercialize its new products that also aim at this aggregation,
including making the necessary adaptations to the specifics of the client.
CONTEXTUALIZATION CPFL Energia is, today, one of the largest companies of the Electric Sector in Brazil, highlighting
among its actions the distribution of electricity. There are already nine distributors that serve about
14% of the total national consumers, located in the Southeast and South regions of the country.
The demand for energy in these companies goes through a sub-transmission system that has
almost all transmission lines and substations that operate in three voltage classes of: 72.5 - 92.4 -
145 kV.
As already pointed out, these companies have been established for a long time. Not only that,
many of them have varied constructive solutions in terms of civil, electrical and electromechanical
projects, depending on their origins, as well as the evolution of the technology they have chosen or
could access throughout their life, including Control, protection, measurement and
communication. In common, such installations are virtually all at the time, with substations and
conventional lines, isolated in the air.
The substations themselves are composed of high-voltage spans of incoming transmission lines,
spans between busbars (double or main plus transfer), connection of power transformers and
connection of capacitor banks, as well as means gaps Output voltages of primary distribution
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network feeders (these are also mostly aerial). Typically, the composition of electrical equipment
in these spans is very similar, given the similarity of functional needs, in terms of acquiring the
values of the electrical parameters necessary for the correct operation (which includes energy
measurement) and, in the event of failures, faults And defects, to the appropriate maneuver of
topological modification of circuits to overcome the difficulties and to maintain, as much as
possible, the continuity of the services, through the connection or disconnection of alternative
sources and transfer of loads.
In terms of high voltage, usually up to 145 kV, line input and power transformer connection spans
are the most common in conventional overhead distribution substations. The main electrical
equipment found in these locations are lightning rods, disconnectors, earthing switches, circuit
breakers, current transformers (CT) and potential transformers (TP). In older substations, there are
still tank-type circuit breakers that use mineral insulating oil, while in more recent installations,
the trend has been to use more modern and efficient, live tank type circuit breakers, initially with a
small volume of Oil and even with compressed air, and then with SF6 gas (sulfur hexafluoride).
With live tank type circuit breakers, however, there is a need for the use of a pedestal-type TC,
which is dispensable in case of dead tank type circuit breakers (which have bushing type TC).
The evident advantages of using SF6 as an insulating medium and of the interruption of the
electric arc in the high voltages, when compared in terms of operation and maintenance to the
previous technologies, allowed the return of the tank type circuit breakers with this gas, because
the use of Bushing has better reliability and lower cost than the pedestal type.
Furthermore, the SF6 allowed the development of compact modular solutions for the substations,
with respect to the aforementioned functionalities with the listed equipment, in sheltered and
weathered armor arrangements. Although of a high initial cost, gas-shielded substations confer
extremely high operational reliability with enormous maintenance reduction and space used for
installations compared to conventional isolated air solutions. And, they greatly reduce field
assembly time and power-up release, since they come pre-tested and pre-commissioned from the
factory.
Finally, in the most recent movement, with the accumulated experience, the main manufacturers
have developed the compact hybrid solutions, so named because they combine in a single
equipment the use of conventional insulation in the air with armored parts in SF6. With this, it is
possible to confer a reasonable degree of compaction to the facilities of a substation without
incurring the high cost of the exclusively gas-shielded.
CPFL does not have gas-shielded substations, but has already incorporated the technology of
compact hybrid maneuvering modules in a few cases, precisely where the limitation of available
space was decisive for its adoption.
MAINTENANCE IN ELECTRICAL SYSTEMS
It is not necessary here to discuss the importance and the details that involve the need to keep
operating the electrical installations of the substations and transmission lines that compose the
electrical systems, since they were implanted and enormously expanded, passing through the great
evolution in terms of the materials , Prospecting techniques, tooling and instrumentation, as well
as applied methodologies and personnel training.
When it comes directly to the subject, CPFL has for some time sought to resolve the impact on its
indicators of the limitation of preventive and corrective maintenance in equipment, especially the
entry gaps of transmission lines, Of transformers. Shutdowns are inevitable and the operating area
is always reluctant to release. Sometimes the time spent on tasks is long, largely due to the length
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of time and obsolescence of components and parts of the equipment in the span, with difficulty in
replacing them, as well as to ensure the work safety of the teams employed, with activities
performed alongside Sectors kept energized in the substation.
The use of mobile substations and transformers (see Figure 1) is traditional in releasing the
transformation spans they replace, but this cannot be counted on when it comes to other
equipment, given the prioritization of the former. However, the quantity of these solutions
available to the needs of the distributors has always provoked a "queue" of use, not to mention that
in many cases its use is impeditive due to access and secure positioning. In addition, there are
often operational constraints, such as the ability to handle prospective shipments on site. Finally,
we must not forget the costs of licenses and traffic releases.
Figure 1 – Mobile Substation
MOBILE, TRANSPORTABLE AND RELOCABLE EQUIPMENT
At the beginning of the year 2000, CPFL was able to obtain a satisfactory cost-benefit from a
manufacturer who developed equipment to replace the power circuit breakers of 138 kV power
transformers, Assumptions in this application. Among these, maximum nominal current up to 420
A (powers up to 100 MVA), maximum symmetrical interruption capacity of 31.5 kA, no reclosing
(only one opening maneuver, with "fast" closing by special built-in Slow closing of the switch
unit) and, above all, be a set that could be assembled and disassembled for transport.
Such a solution was very successful and CPFL uses it to date, having bought another unit this
year. However, it is not possible to relinquish relays, including the initial start-up, in line circuit
breakers, not to mention the nominal current requirement of at least 1250 A (ideal minimum
carrying capacity of 300 MVA). At that time, attempts to make a mobile circuit breaker cost
prohibitive costs.
With such experience, a new concept emerged as an innovation for CPFL. Until then, the idea was
that equipment designed to temporarily replace another, in typical maintenance or emergency
situations, after which it would be moved to another location and to another similar service, would
normally be built on the platform of a trailer, or Semi-trailer, to be drawn by mechanical horses
and transported to the concessionaire's facilities along the geographical service area. This is the
case for substations and mobile transformers, by far the most important ones for use. But
equipment that is mountable and can be dismantled with each use can dispense with the rolling
part, being transported in trucks that the concessionaire already has for other tasks, or eventually
rented in the market. This provides an appreciable reduction in the cost of manufacturing and even
of maintenance, also dispensing licenses to travel. Of course, there should be resources for lifting
in the loading and unloading operations, which are usually already part of the concessionaire's
plant.
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Then, with the expansion of CPFL's electrical systems, substantiated in consolidated works plans,
synchronized with the regulator's tariff revisions, and, to some extent, the pressure to execute a
growing equipment maintenance program in 2015 The opportunity to budget and seek again a
solution to the gaps of transmission line inputs, once again thinking of a mobile circuit breaker.
Considering that technological evolution has allowed the design and construction of increasingly
compact, robust and functional electrical equipment, in addition to being associated in single
armored modules with dimensions and weights combined with the improvement in the reliability
and availability of their functions, offered by a favorable market. Concept was a compact hybrid
module with SF6 gas insulation attached to a rigid platform that could be simultaneously hoisted
for a trailer or semi-trailer by road, and dragged, when on the subsoil or line Position between
frames and supports structures of the existing equipment, by having a smooth lower surface and
made for it.
Then, from a technical specification of CPFL with the above requirements, ABB designed the new
equipment based on its already successful three pole operation compact hybrid module type PASS
M0, nominal voltage 145 kV, current 2500 A and containing the functions of a circuit breaker
(including a quick-reclosing cycle, typical for transmission lines), a disconnector with integrated
grounding blade and bushing type current transformers (for protection and measuring IEC 62271-
205: 2008 - Compact switchgear assemblies for rated voltages above 52 kV - and the requirements
of IEEE 693-2005 - Recommended Practice for Seismic Design of Substations.
And the modifications that ABB had to introduce in order to meet the necessary characteristics led
to different solutions for the maximum dimensions, in particular the height, while at the same time
ensuring the minimization of the total weight for lifting and transport, to fit the Traffic legislation
allowing free traffic, without limitation of schedule, issuance of special licenses and scheduled
transportation routes, according to Resolution No. 210/2006 of the National Traffic Council. And
also to securely allow embarkation and disembarkation actions, from the road and ground trailers
platforms, through CPFL's standardized guinea-pigs for their works and maintenance tasks. With
this, the relocability of the equipment is standardized.
GENERAL DETAILS OF THE RELOCABLE COMPACT HYBRID MODULE
The single line diagram specified for the equipment is shown in Figure 2. In the spans to which it
will be installed, the breaker housing should be facing the side of the power source, usually a
transmission line. The features that the compact hybrid module embeds allow similar conventional
equipment to be temporarily replaced, maintained, unitarily or all at once.
Figure 2 – Single line diagram
In order to guide the manufacturer, CPFL has included in its specification a semi-trailer
dimensional design of the market, as a minimum condition in the design of the project, aiming the
shipment and transportation of the relocatable compact module (Figure 3).
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Figure 3 - Example of Road Semi-trailer
Thus, ABB submitted its design to CPFL and final design approval is illustrated in the set of
drawings in Figures 4 to 7 below. Further on, they follow Figures 8 through 33, with photographs
of what was actually manufactured and delivered, showing various details.
The total weight of the assembly, considering the compact hybrid module and its platform, was at
4056 kgf. The central control cubicle weighs 350 kgf. The crosshead and lifting cables weigh
almost 405 kgf. Thus, the total transport weight is almost 4810 kgf
Figure 4 – Profile View
Figure 5 – Top View
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Figure 6 – Lifting Mounting
Figure 7 – Positioning and risk zone
Fig. 8: Lift cradle
Fig. 9: Suspended lifting cradle, with cables
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Fig. 10: Assembly lift for common truck
boarding
Fig. 11: Detail of the hoist, showing the
dedicated crosshead and its cables
Fig.12: Set of steel suspension cables and
washers for attachment to lifting eyelets
Fig.13: Circuit Breaker Drive
Fig. 14: Disconnector and earthing switch
chamber with viewport window
Fig. 15: Disconnector and earthing switch
drive
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Fig. 16: SF6 Gas Density Monitor and
Pressure Gauge
Fig. 17: Secondary bushing CT terminals
Fig. 18: Local Control Cubicle
Fig. 19: LV Cables
Figura 33 – High Voltage Hybrid & Compact Relocable Switchgear
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CONCLUSION
This work aimed to present a synthesis of the development of a "tool" for use in field activities in
distribution substations, and even in spans along transmission lines, aimed at the implantation and
expansion works, as well as maintenance services (programmed And emergency), typically carried out
on high voltage electrical equipment up to 145 kV.
The tool, the compact hybrid module of relocatable maneuver, was conceived from the consolidation
of the last technological developments of the manufacturers of electrical equipment of high tension,
aiming at reliability, robustness, reduction of the need of maintenance and reduction of the cost of the
electrical installations where they are applied, both at implantation and throughout the useful life. In
addition, the practical requirements of the user, that is, the electricity distribution companies.
It should also be noted that in CPFL, the concept of relocability, coupled with that of modularity, has
already been extended to other components of an energy substation, some of which already exist, such
as mobile substations and mobile transformers, and others Also of recent design and acquisition and
concurrent with that of this relocatable hybrid module, i.e. relocatable medium voltage reclosers and
mobile voltage regulators. With this, it is even possible to set up temporary substations, albeit with
some restrictions.
Thus, with the contribution of the manufacturers and suppliers of equipment, there was a significant
leap for distributors to face, at an acceptable cost-benefit, the constructive, operational and
maintenance challenges of their electrical systems, which have a huge variety Of technical solutions,
stemming from a legacy that merges with the incessant technological evolution in search of present
efficiency.
BIBLIOGRAPHY
Type here your bibliography in the order they are mention in the text. Times New Roman, 11. Follow
the examples.
[1] Norma Técnica IEC nº 62271-205/2008 (Compact switchgear assemblies for rated voltages
above 52 kV).
[2] Norma Técnica IEEE Std. 693-2005 – Recommended Practice for Seismic Design of
Substations. [3]Prospectiva del Sector Eléctrico 2002-2011. (Secretaría de Energía. Mexico,
2002).
[3] Especificação Técnica CPFL GED nº 16665, versão 1.0, de 06/11/2015.
[4] Resolução CONTRAN nº 210/2006, de 13/11/2006.