THE ANTAS RIVER HYDROPOWER COMPLEX - · PDF fileTHE ANTAS RIVER HYDROPOWER COMPLEX - CERAN 1....

THE ANTAS RIVER HYDROPOWERCOMPLEX - CERAN

CA

STR

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HPP

14 D

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HPP

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HPP

Authors: Marco Aurélio Fernandes, Vendolino Fischer and Marcelo Wood Chiarello

Main Brazilian Dams III

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THE ANTAS RIVER HYDROPOWERCOMPLEX - CERAN

1. INTRODUCTION

The Antas River Power Complex consists of the CastroAlves, Monte Claro and 14 de Julho HPP plants. It belongsto CERAN, the Antas River power company (CompanhiaEnergética Rio das Antas), comprising the consortiumof CPFL - GERAÇÃO DE ENERGIA S.A., CompanhiaEstadual de Geração e Transmissão de EnergiaElétrica – CEEE-GT – RS and Desenvix S.A.

The CERAN Complex consists of the Antas Riverwater power project with the construction of threehydropower plants totalling 360 MW of installed capacity,and their step-up substations and power lines for theiruse and the 230 kV substation connecting to the nationalpower grid.

The power plants in the CERAN Complex will add360 MW to the installed capacity of Rio Grande do Sulstate, which means approximately ten percent of thecurrent electricity demand in Rio Grande do Sul and helpsthe state achieve its goal of power self-sufficiency.

During construction of the complex, CERAN isadopting groundbreaking and special solutions,constantly endeavouring to interfere as little as possiblein the natural environment. An example of suchinnovations is the opening of tunnels to prevent theformation of large reservoirs and, thereby, substantiallyno. 2 on 2nd April and unit no. 3 on 6th June 2008.

The 14 de Julho hydropower plant is underconstruction and it is expected to start commercialoperation in December 2008. Since this article was writtenin mid-2008 some aspects of this plant described hereinmay not as closely represent the as built project.

1.1. LocationThe three hydropower plants are located on the Antas

River, a drainage basin of the River Taquari-Antas in thestate of Rio Grande do Sul (see Figure 1).

Castro Alves HPP, the farthest upstream from theenterprise, has the dam located between the counties ofNova Padua and Nova Roma do Sul between thegeographic coordinates of 29º 00' 30" South and51º 22' 45" West.

Monte Claro HPP dam, downstream from the CastroAlves HPP, is on the geographic coordinates 29º 01' ofSouth latitude and 51º 30' West longitude between thecounties of Veranópolis and Bento Gonçalves.

The 14 de Julho HPP, downstream from Monte ClaroHPP, lies between the counties of Bento Gonçalves andCotiporã, with the powerhouse installed in Cotiporã

County, on geographic coordinates 29o03' South and51o40' West.

1.2. SuppliersConsórcio Fornecedor do Complexo Rio das Antas

(COFRAN) is in charge of the enterprise, involving thecompanies Construções e Comércio Camargo CorrêaS.A., Alstom Brasil Ltda. and Engevix Engenharia S.A.

These suppliers are responsible for the following:• Construções e Comércio Camargo Correa S.A: Jointventure management, civil works construction,electromechanical installations and supply of

Figure 1 - Location of CERAN Complex Plants


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transmission lines and substations• Alstom Brasil Ltda: Supply of turbines, generators,hydro-mechanical systems, lifting equipment, auxiliarypower systems, transmission lines with upstream-downstream connection and associatedtelecommunication systems• Engevix Engenharia S.A.: Preliminary design, finaldesign and supply of the mechanical auxiliary systems

2. GEOLOGICAL CHARACTERISTICS

2.1. Regional GeologyThe region where the plants are located is

characterised by prevailing extrusive rocks of the SerraGeral Formation subdivided in basic (tholeitic basalts)and acid (riodacites) terms. These are associated withan intense diastrophic phenomenon, which enabled theemission of lava through fissural volcanism between theend of the Jurassic and Lower Cretacean.

The works site is affected by structural lineamentswith preferential directions to the NE and NW, whichstrongly condition the drainage in the region, includingthe course of the Antas River in many stretches, reflectedin its bends and straight stretches.

2.2. Local GeologyThe foundation of the abutments of the dams in the

complex lies on flows of sound and only slightly fracturedbasalt, reached after removing altered horizonsassociated with relief joints parallel to the ground surface.

The foundation surface of the structures situated onthe river bed, belonging to the 14 de Julho HPP, are densebasalt and basaltic breccia. Unlike the others, the 14 deJulho had a remarkable occurrence of an extensive alluvialdeposit on the river bed, consisting of pebbles and gravelof basalt rock, associated with a paleochannel.

A large part of the underground excavations were ingood sound rock mass and mostly with few fractures,the surfaces receiving treatments stipulated by the Bartonclassification "Q". However, in several places of theprojects the rock mass was affected by high in situstresses characterised by occurrences of rock burst instretches excavated in dense basalt. These rock burstswere found in the penstocks and powerhouse vault of 14de Julho HPP and in the headrace tunnels of Monte Claroand Castro Alves HPPs, requiring special treatment forstabilising the excavated surfaces.

The fracturing of the basalt rock is predominantly sub-vertical with spacing between the fractures varying fromcentimetres to various metres. Sometimes there aresigns of persistent intense inclined and sub-horizontal,planar to conchoid jointing, with spacing in centimetresto decimetres, which associated with the sub-vertical

fracturing conditioned the need for intense treatments tothe excavation walls.

3. HYDROLOGY, HYDRAULICS ANDENERGY STUDIES

3.1. Physiographic Characterisation of BasinThe Antas River drainage basin as far as the site of

the dam axis of 14 de Julho HPP covers an area of around12,664 km2.

The Antas River starts in the Serra Geral,approximately at elevation 1150 m, in São José dosAusentes County, flowing westwards to meet the RiverTaquari.

Until the Castro Alves dam axis, it is 260 km in lengthand a difference in level of 910 m. Then it flows to theMonte Claro dam axis over a distance of 270 km with adifference in level of 1000 m, and to the 14 de Julho damaxis flows for 280 km with a difference in level of around1050 m.

3.2. ClimateThe headwaters of the Antas River drainage basin are

situated in the Serra Geral, more precisely in the regionof the county of São José dos Ausentes, over a distanceof approximately 50 km from the coast, draining inlandas far as the site of the CERAN hydropower plants.

The climate studies undertaken for the Antas Riverbasin and micro-climate in the region of the plants werebased on the data of two climatological stations andtwelve rain gauge stations.

In the region where the CERAN hydropower plantsare installed, the average temperatures vary from8o to 27º C during the year.

The annual average total rainfall is approximately1,630 mm, varying between a maximum of 2,240 mm in1983 and minimum of 1,184 mm in 1964. Its spatialvariation is not very accentuated, varying from 1,500 mmto 1,750 mm.

3.3. Streamflow characterisationThe characterisation in monthly terms of the surface

water potential of the Antas River for the sites of the powerplants in the CERAN complex was based on data foundin the Monte Claro streamflow station. The data of thestreamflow stations of Passo São Bernardo and PonteRio das Antas were also used to provide more consistentstudies of the station's data and to fill in gaps in thereadings,.

3.4. Natural FlowsThe results of the studies undertaken are presented

in the following tables, for each plant.


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3.5. Energy Studies3.5.1. Feasibility Studies

The feasibility studies were based on data referringto head division proposed in the inventory studies ofCEEE, the state power company of Rio Grande do Sul(Companhia Estadual de Energia Elétrica do Rio Grandedo Sul) dated 1993.

To determine the capacity to be installed in the plant,dimensioning studies of the structures andelectromechanical plant affected by the variation inmotorising the plant for installed capacities of 90, 110,130, 150 and 170 MW were performed.

These energy studies for each plant resulted in thefollowing:• Castro Alves HPP - total capacity of 130 MW, to beinstalled in a single step, assured energy of 64 MW.• Monte Claro HPP - total capacity of 130 MW, to beinstalled in a single step, assured energy of 59 MW.• 14 de Julho HPP - total capacity of 100 MW, to beinstalled in a single step, firm energy of 50 MW.

3.5.2. Revision of Type and Number of UnitsDuring the preliminary design stage the type and

number of units of the CERAN power plant complex wereoptimised.

When refining the studies the recommendation of thetype and number of units to be installed at the CastroAlves HPP presented in the feasibility studies wereconfirmed; in other words, the three Francis turbines werekept.

For Monte Claro HPP, considering the low head andlimits imposed by the operating range of the Francisturbines, their substitution by two Kaplan machines, moreflexible in operational terms, was more suitable, principallyconsidering the operation coordinated with the CastroAlves HPP, in order to optimise the regulated flow in thatplant.

For the 14 de Julho HPP, however, the three generationunits were reduced to two, so that the low hydraulicitysituations are also compensated by the operation of thewater stored in its reservoir and a coordinated operationwith the upstream plants.

Considering that the difference between the costs ofequipment for adopting a Kaplan turbine is higher thanthe cost of the Francis turbine, but with lower costs inthe civil works, and also considering the results of the


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engineering and environmental studies undertaken, theplants are economically attractive.

4. DESCRIPTION OF LAYOUTS

4.1. Transmission SystemThe Restricted Use Transmission System for

integrating the Antas River Power Complex correspondsinitially to access to the basic network of Monte ClaroHPP, in the 230 KV configuration, by implementing thefollowing facilities:• Monte Claro HPP step-up substation- 13.8 /230 KV;• Monte Claro interconnecting substation,230 KV; and• Transmission line, simple circuit, 230 kV, over a lengthof 1.0 km, connecting the Monte Claro HPP step-upsubstation to the Monte Claro interconnecting substation.

The CERAN Complex power plants will be dispatchedin three load levels - heavy, medium and light - to producetheir assured energies, totalling 173 Mw.

Monte Claro, Castro Alves and 14 de Julho HPPs areconnected to the Monte Claro interconnecting substationindividually by 230 KV transmission lines, with a 63 MCMcable simple circuit, which interconnect these plantsindividually to the Monte Claro interconnecting substation

4.2. General Description of Layout4.2.1. Castro Alves HPP

The layout of the works made use of a bend in theAntas River, so that the dam, spillway and diversionstructure are located in the upstream stretch of this bend(Figure 2). The hydraulic generation circuit intercepts theloop of the river on the right bank, so that the totaldifference in level to be used on the site is 92 m, around40 m of which is obtained by the dam and the other 52 mby the natural difference in level of the river along thebend in that stretch.

The layout consists of the following structures:• Concrete gravity dam incorporating an overflow

spillway;• Diversion structure with four (4) sluices (4 x 10 m);• Generation system consisting of an intake, headrace

tunnel around 7,093 m long and a circular arch section11.90 m in diameter, surge chamber, three penstocks4.00 m in diameter, power house with three machinestotalling 130 MW of installed capacity and a tailracechannel for returning the water to the river (Figure 3, 4and 5).

ReservoirThe Castro Alves hydropower plant reservoir has an

area of approximately 5.1 km² and volume of 91.77 hm³ atits normal maximum water level at El. 240.00 m. With themaximum flood level the reservoir area attains 5.95 km².

River Diversion and Control and CofferdamsDiversion Sluices

There are four sluices with a rectangular section of4.00 m wide by 10.00 m high and 50.00 m long. Both theinflow and outflow sill are at El. 192.00 m.

The sill of the inlet and outlet canals is atEl. 197.00 m and 22.00 m in width. The inlet channel isaround 100 m and the outlet around 90 m long.

Next to the inlet is the final closing structure of thesluices, with the top at El. 210.00 m. This structure hasfour openings, one corresponding to each sluice.

EquipmentThe set of sluices for the final closure of the gates

was installed in the inlet structure with the spillway atelevation 192.00 m.

They are closed by means of a sliding stop-loginstalled in the downstream slot. The upstream slot isdesigned to have a fixed wheel gate only if the stop-logjams.

There was no plan to recover these stop-logs afterplugging the sluices.

Main CofferdamsTwo rock-fill cofferdams with clay waterproofing were

built upstream and downstream from the dam axis todivert the river.

The upstream cofferdam, with its top at elevation215.00 m, protects the dam construction area againstfloods of 2174 m3/s, corresponding to the recurrenceinterval of 10 years in the dry season.

The downstream cofferdam, with top at elevation202.50 m, protects the drained area against floods of upto 10 years, compatible with the upstream cofferdam.

River Diversion StagesThe river diversion occurred in two different stages,

as follows:• 1st Stage - the river remains on the river bed without

narrowing.The services for the hydraulic generation circuit

structures on the right abutment of the river and theapproach canal and sluices and closing structure on theleft bank were undertaken with the river on its naturalbed.

• 2nd Stage - using the sluices.The 2nd stage diversion was undertaken using four

sluices (4 x 10 m).The dam/overflow spillway works on the river bed were

protected against flooding with 10 years recurrenceinterval during the dry season, by an upstream cofferdamat elevation 215 m and one downstream at elevation202.50 m.

After completing the works on the dam/spillway andin the generation circuit, the river was closed using thegates at the top of the sluice structure, at EL 210.00 mby means of a travelling construction crane.


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Figure 2 - Castro Alves HPP - Dam

Dam and SpillwayThe dam with a built-in overflow spillway has a gravity

section in roller-compacted concrete (RCC). The spillwaystretch is 240 m in length and tops at El. 240.00 m. Themaximum height on the river bed is around 47 m. Beyondthe spillway stretch on both abutments, the dam crest isat El. 247.50 m, extending for 108.00 m.

The dam's geometry corresponds to a gravity structureusing the RCC technique to El. 234.38 m and conventionalconcrete from there on. The upstream face is vertical.The downstream side of the dam stretch has a gradientof 1V:0.70H.

On the downstream side, the embankment is confinedby a zone of conventional concrete, with average width


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of 0.65 m raised jointly with the RCC layers.The drainage system and inspection of the RCC

embankment has a longitudinal gallery. This gallery isequipped with a dewatering system for drained water bygravity and pumping. The main drainage curtain was builtfrom this tunnel.

Figure 4 - Castro Alves HPP - Downstream Layout - 3D View

Figure 3 - Castro Alves HPP - Downstream Layout

The overflow spillway discharges into the river bed. Itwas conceived with a runoff capacity for a 10,000 floodwith inflowing peak of 9,011 m³/s and the reservoir waterlevel at El. 246.36m.

Photo 1 shows an aerial view of the dam. Photos 2and 3 the overflow dam spilling.


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Residual Discharge SystemIn order to meet environmental requirements, the

residual outflow was stipulated at 17 m³/s and onweekends and public holidays an extra flow of 83 m³/s,for a period to attend rafting now existing in this stretchof the river.

Supply CircuitThe hydraulic generation circuit consists of the

following structures:• The headrace was excavated in rock and is

approximately 30 m long with a minimum width of 15 mat the canal base.

The channel is designed for a maximum velocity ofless than 1.50 m/s, considering the normal maximumlevel in the reservoir at El. 240.00 m.

- Intake• Headrace tunnel• Penstocks• Tailrace tunnel• Tailrace excavated in rock and around 35 m in lengthand 30 m in width. This tailrace was dimensioned for amaximum velocity of 3.00 m/s, in the condition ofmaximum flow turbined by the three units.

IntakeThe Castro Alves HPP intake on the right bank of

Antas River has a hollow gravity concrete structure. Thisstructure connects to the headrace tunnel through a5.50 m long transition.Figure 5 - Castro Alves HPP - Downstream Layout - 3D View

Photo 1 - Castro Alves HPP - Aerial View of the Dam


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It was dimensioned for a rated flow of 176 m³/s inorder to operate under a maximum depletion of 1.00 m ofthe reservoir's normal maximum water level, only for dailyflow compensation.

The hollow gravity concrete structure topping atEl. 250 m will have total width of 15.10 m. Closing theheadrace tunnel for maintenance will be done by closingboth openings with stop-logs 4.55 m wide by 8.00 mhigh.

Headrace tunnelThe water for the turbines is supplied using a tunnel

connecting the intake to the surge chamber around7.090 m long. The maximum flow of this tunnel is176 m3/s. The geometry of the tunnel has a loweredcircular arch cross-section 11.90 m in diameter.

The headrace tunnel for turbine operations operatesat speeds of 2.27 m/s, lined with shotcrete on the arches.

Surge ChamberDue to the extent of the hydraulic supply circuit, it

was considered necessary to implement a surgechamber. The surge chamber is located around 7090 mfrom the inlet of the headrace tunnel 149 m distant fromthe axis of the generator units.

The 21 x 100 m dimensions of the chamber werealso adopted based on checks on hydraulic stability ofthe oscillations. Load acceptance and rejection

conditions defined the maximum and minimum waterlevels in the surge chamber at El. 252,00 m and229.70 m, respectively.

Lined PenstocksThe penstocks are built after the surge chamber, with

a small horizontal stretch and vertical stretch descendingto the level of the line of distributors. The concrete-coatedstretch is 4 m in diameter and 180 m in length. The metal-armoured stretch has a diameter of 3.30 m and length ofaround 20 m.

Powerhouse - Civil WorksAccess to the site is downstream through a road

connected to the main access to the project. (Photo 4and 5).

The powerhouse is underground, with three blocksfor the generator units, each block 12.10 m in width andaround 17.90 m in the cross section (Figures 6 and 7).The total lengthwise section including an area forinstallation and multi-use spaces is 87.5 m.

The galleries of electrical equipment, where the currentlimiting reactors, the supply circuit breaker of the auxiliaryservices, general service distribution boards, set of 13.8kVhandlers and unit substations are located, were designeddownstream from the generating unit blocks.

The toilets, battery room, battery chargers, exhaustionplenum and sewage pumps and repair shops are situatedin the block of the assembly area.

One of the ventilation and exhaustion rooms wasdesigned and built in the ventilation tunnel of the mainnave of the engine room and the other in the ventilationtunnel of the electrical gallery.

The local control rooms will be equipped to permitcontrol of the generating units, containing the controlboards and instrumentation required to fulfil the followingtasks: digital control of the unit, regulation, protection ofthe unit and telecommunication systems.

In the area outside the powerhouse are situated theair intake for the ventilation system, the drinking waterreservoir, the track for the transformers, step-uptransformers and the water-oil separation tank.

Powerhouse - Mechanical EquipmentTurbines

The three hydraulic turbines are Francis vertical axismodels, with rated capacity of 44.58 MW adapted fordirect coupling to three-phase synchronous generatorsof 48.54 MVA.

Overhead travelling craneAn overhead travelling crane indoors was planned for

shifting loads during assembly and maintenanceoperations of the turbines, generators and otherequipment of the plant.

Photo 2 & 3 - Castro Alves HPP - Overflow Dam Spilling


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Photo 4 - Castro Alves HPP - Aerial View of Downstream Area

Photo 5 - Castro Alves HPP - Aerial View of the Powerhouse


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Draft Tube Stop-logTwo stop-logs for closing a generating unit were

planned for maintenance activities of the turbines.

Step-up SubstationThe Castro Alves step-up substation is divided into

three sectors: the mid-voltage sector, transformationsector and the 230 kV sector.

The transformation sector consists of three13.8/130 kV single-phase step-up transformers, whichwill comprise a three-phase bench of 150 MVA.

Figure 7 - Castro Alves HPP - Powerhouse - Cross-section

Figure 6 - Castro Alves HPP - Powerhouse - Longitudinal Section

The transmission line between the step-up substationof the Castro Alves HPP and connecting substation ofMonte Claro is in 230 kV, consisting of a three-phasecircuit.

4.2.2. Monte Claro HPPGeneral Description of Layout

The layout of the Monte Claro HPP works (Figure 8)consists of the following structures:• The dam is RCC roller-compacted concrete (Figure 9).Included in this dam structure is the overflow spillway.


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• On the right abutment is the surface spillway structure.• A generation system consisting of intake, headracetunnel with rectangular-arch section 12.50 m in height,surge chamber, two penstocks 6.66 m in diameter,powerhouse housing two machines totalling 130 MW ofinstalled capacity and a tailrace for returning the waterto the river.In order to build this dam/spillway structure, the AntasRiver was diverted using the structures on the right bank:• By the rectangular-arch section tunnel, 13 m in diameterand 324 m in length, to be installed on the right side ofthe spillway with gates, and therefore at the end of theright abutment.• By the spillway structure with gates, but still withoutinstalling the ogee. Therefore, at the river diversion stage,this spillway had the sill lowered and the water ran offwith the gates fully open.

This ogee was concreted after concluding the dam/spillway structure.

ReservoirThe Monte Claro HPP reservoir covers an approximate

area of 1.4 km² and has a volume of around 12 hm³ at itsnormal maximum water level. The area of the reservoirfor the water level with the inflow of the probable maximumflood is 2.5 km².

River Diversion and ControlThe intake structures of the diversion tunnel, with slots

for two stop-logs and two fixed wheel gates, a rectangularcross section 4.00 m wide by 10.00 m high are set atEl. 123.00 m in order to permit the river diversion with alittle difference in level of 3.00 m between upstream/downstream.

The most frequent floods were discharged throughthe diversion tunnel jointly with the lowered sills of thespillway.

After concluding the works of the overflow dam andthe operating tests of the spillway equipment with radialgates, the stop-logs were placed at the inlet to thediversion tunnel and the tunnel plug was concreted.

Main CofferdamsTwo cofferdams were built for the diversion: one

upstream and the other downstream from the dam axis.Both were in rockfill and waterproofed using clay material.The upstream cofferdam, with top at El. 144.00 mprotected the construction area of the dam against floodsof 3847 m3/s, corresponding to a 10-year recurrenceinterval during the dry season. The top of the cofferdamdownstream was at El. 139.50 m.

Figure 8 - Monte Claro HPP - Upstream Layout


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Figure 9 - Monte Claro HPP - Overflow RCC Dam - Cross Section

River diversion stages1st Stage - With the river continuing to flow in its natural

course, the diversion tunnel and concrete structures werebuilt on the right bank at the outlet for the positioning ofthe stop-logs and spillways structure with gates and alowered sill during the river diversion stage.

The structure of the inlet of the diversion tunnel onthe right bank, with two openings with a rectangular crosssection of 4.00 m wide by 10.00 m high, and a sill atEl. 123.00 m as designed to permit the discharge of thenormal river flows.

The spillway with lowered sill has two radial gates12 m wide by 19.68 m total height. This structure wasbuilt with a lowered sill at elevation 125.00 m to permitits use during the second stage of the diversion.

2nd Stage - At this stage, the water flowed through thediversion tunnel and lowered sill spillway, built during thefirst stage diversion on the right bank.

After concluding the dam/overflow spillway works onthe riverbed and abutments, the final concreting of thespillway sill on the right bank was finally done toEl. 132.00 m. This activity was undertaken by installinga stop-log in each bay of this spillway. After finalising theconcreting of the last bay, the corresponding stop-log

was removed and all bays closed by lowering the radialgates.

Dam and SpillwayThe dam in the stretch with the incorporated overflow

spillway has a gravity section in roller-compactedconcrete (RCC), over a total length of around 180 m andcrest at El. 148.00 m. Outside this stretch, the dam onboth abutments is 70 m total length with the top atEl. 158.00 m. Its maximum height on the river bed isaround 27 m.

A spillway with two radial gates 12.00 m wide and19.68 m total height, associated to the overflow spillway,was built on the right bank, with the crest atEl. 132.00 m. The top of this spillway structure is atelevation 158.00 m. A bridge was built upstream from theradial gates at El. 158 m, for access to the control roomand stop-logs, and downstream from the radial gatesanother access bridge for placing stop-logs downstreamfor the construction of the ogee arches and protection forfuture repairs.

The set with the overflow spillway and spillway withgates was designed for capacity to discharge the10,000 flood. The peak outflow of this flood is17,038 m³/s. Since the reservoir has reduced dimensions,


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there is no reservoir flood routing and the exceptionalmaximum water level of the reservoir reachesEl. 156.52 m.

The geometry of the dam corresponds to a gravitystructure, adopting the RCC technique to El. 142.00 mand in conventional concrete from there up. The upstreamface is vertical. The downstream face of the non-overflowstretch has a slope of 1V:0.75H below El. 152.38 m, andvertical above this elevation.

Residual Outflow SystemIn order to meet the requirements during the plant's

operation, an echological outflow system was installed

Photo 6 - Monte Claro HPP - Dam

Photo 7 & 8 - Monte Claro HPP - Overflow Dam Spilling

(in the dam) with a capacity to discharge 5.50 m³/s.An increase of this flow can be achieved by partiallyopening the spillway's radial gate.


following structures:• The hollow gravity intake 15.00 m wide, 30.0 m highand crest at El. 158.00 m, is fitted in the right abutment;• Headrace tunnel around 1,170 m long and with arectangular-arch cross-section of 12.50 m in height andwidth;• Surge chamber with area equal to 1250 m²;• Two penstocks with internal diameter of 6.66 m andlengths of around 101.00 m, with armouring in 60.00 meach;• Semi-indoor powerhouse, with maximum height of55.00 m and provided with two Kaplan units.

The downstream and upstream layout is shown inFigure 10 and the powerhouse section in Figure 11.

Headrace CanalThe headrace canal is excavated in rock and is

approximately 40 m long with a minimum width of15.00 m at the canal base.

The canal is designed for a maximum velocity below1.50 m/s, considering the normal maximum level atEl. 148.00 m.

Headrace TunnelThe water for the turbines will be supplied through a

headrace tunnel connecting the intake to the surgechamber, approximately 1140 m in length.

For the turbine operations the headrace tunnel willrun at velocities of 2.70 m/s, and will be lined withshotcrete in the arch, floor in rolled concrete and the restof the perimeter unlined rock.

Tailrace TunnelTo return the turbined flows to the river, tailrace tunnels

are built in excavated rock with shotcrete lining.

IntakeCivil Works

The Monte Claro HPP intake consists of a rectangular-section structure directly connecting and separately tothe headrace tunnel through a transition 12.50 m in length.

The hollow gravity concrete structure, with crest atEl. 158.00 m, has a total width of 15.00 m and height ofaround 30 m, from its foundation.

It is planned to install in the intake two stop-logs tobe used for maintenance of the emergency valvesprovided next to the powerhouse.

EquipmentTrashracksThe intake water passages are provided with


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Figure 10 - Monte Claro HPP - Downstream Layout

Figure 11 - Monte Claro HPP - Surge Chamber & Powerhouse


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trashracks panels installed next to the inlet, to retainlarge solid materials to prevent damage to the turbines.

Stop-logStop-logs are planned to close each span of the intake

and that together with its fixed parts can withstand thehydrostatic pressures corresponding to the normalmaximum water level (at El. 148.00 m) and the mostfrequent floods (151.00 m), in normal and exceptionalconditions, respectively.

Low Pressure Power TunnelThe low pressure power tunnel in rectangular-arch

section has a width and height of 12.50 m.The 12.50 m long transition in reinforced concrete is

in its initial stretch of the pressure section of the tunnel.The power tunnel was treated using shotcrete on the

arch and walls.The rock trap was installed to retain the stones that

may loosen from the roof and walls of the tunnel.

Surge ChamberDue to the extent of the hydraulic circuit, it was

considered to build a surge chamber, located around1,170 m from the headrace tunnel entrance, for thepurpose of hydraulic stability of the generation circuit.Inside the chamber are two concrete structures in whichwill be installed the stop-logs and fixed wheel gate. Thestop-log is shifted by using a lifting beam operated withthe surge chamber gantry crane. The concrete structuresare approximately 40 m in height and 10 m in width each.

PowerhouseMonte Claro has an outdoor shaft powerhouse built

in reinforced concrete and equipped with two Kaplanturbines, totalling an installed capacity of 130 MW.

Access to the site of the installation area /powerhouseis through an access tunnel from El. 132.70 m in thetransformer yard.

The powerhouse, with two blocks for the generatingunits, is 22.00 m wide and around 20.10 m in the crosssection. The total longitudinal section including theassembly and unload areas is 77.45 m.

Loads inside the powerhouse will be shifted byoverhead travelling crane, with capacity for 200 kN, whichwill move over a rail track.

Situated in the area outside the powerhouse are theair intake room, the drinking water reservoir, thetransformer and step-up transformer transfer track, thewater-oil separation tank and the insulating oil tanks.

Access to the tunnels will be made by stairs or lift,which attends the floors and will descend fromEl. 133.00 m to El. 101.75 m.

The electromechanical tunnels are downstream fromthe generating units and their levels are: 112.25 m,119.25 m and 126.25 m.

Photo 9 shows an aerial view of the powerhouse andsubstation.

Powerhouse - Mechanical plantTurbines

The two hydraulic turbines are Kaplan, with ratedcapacity of 67.10 MW, under a rated head of 37.75 mwith flow of 191.38 m³/s and performance of 94.10%.Rated velocity of 150.0 rpm is suitable for direct couplingto three-phase synchronous generators of 72.90 MVA.

Overhead travelling craneAn overhead travelling crane for working indoors was

planned for shifting loads during installation andmaintenance operations of the turbines, generators andother equipment of the plant.

Draft Tube Stop-logTwo stop-logs for closing a generating unit were

planned for maintenance activities of the turbines.The stop-logs, interchangeable with each other,

together with their fixed parts, will be able to withstandthe hydrostatic pressures corresponding to the normalmaximum water levels, El. 106.60 m, and maximummaximorum of the tailrace at El. 131.00 m, in normaland exceptional loading conditions, respectively.

Powerhouse - Main electrical plantGenerators

The two generators are three-phase, synchronous,with vertical axis, for indoor installation, and each isinstalled in a chamber consisting of a concrete shaft,closed by steel covers at the top.

Each generator is connected to the mid-voltage sectorof 138 KV of the step-up substation by an insulated-phase busbar.

Step-up SubstationThe step-up substation of Monte Claro HPP is divided

into three sectors: one mid-voltage, one transformationsector and the 230 kV sector.

The transmission line between the step-up substationand interconnecting substation is in 230 kV, simple circuit,one cable per phase.

Photo 9 - Monte Claro HPP - Powerhouse & Substation


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Monte Claro Interconnecting SubstationThe interconnecting substation 230 kV has a layout

and management scheme in double buses with four-switch circuit breaker; the use of three modules for thetransmission lines are restricted for the Castro Alves HPP,Monte Claro HPP and 14 de Julho HPP, one module ofan interconnecting bus circuit breaker and four modulesfor the transmission lines to be sectioned next to theMonte Claro substation, Eletrosul Farroupilha-Nova Prata2 and Eletrosul Farroupilha-Passo Fundo.

The 230 kV transmission lines Eletrosul Farroupilha-Nova Prata 2 and Eletrosul Farroupilha-Passo Fundo willbe sectioned and headed in four modules of theinterconnecting substation.

4.2.3. 14 de Julho HPPDescription of Layout

The layout of the 14 de Julho HPP has the followingstructures (Figures 12 and 13):• Diversion by means of the lowered structure of thespillway with gates, and a flood outflow capacity of4,055 m³/s;• Gravity concrete dam with overflow spillway• Surface spillway equipped with two fixed wheel gates;• Generation system consisting of intake, two headracetunnels with a rectangular-arch section and undergroundpowerhouse housing two Kaplan machines with steelspiral casing, with a total installed capacity of 100 MW.

Photo 10 shows an aerial view of the river bend andthe hydro-power plant.

Figure 12 - 14 de Julho HPP - Upstream Layout


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Figure 13 - 14 de Julho HPP - Downstream Layout

Photo 10 - 14 de Julho HPP - Aerial View


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ReservoirThe 14 de Julho HPP reservoir covers an area of

approximately 5.0 km² and has a volume of 55 hm³ at itsnormal maximum water level at El. 104.00 m.

River Diversion and Control and CofferdamsDiversion Structure

The river was diverted by using the lowered sills ofthe spillways with gates, on the left bank.

Main CofferdamsFor the river diversion, two clay-waterproofed rock-fill

cofferdams were built.The upstream cofferdam was topped at El. 96.00 m

and protected the dam construction area againstincoming floods of 4,055 m3/s, corresponding to a10-year recurrence interval during the dry season.

River Diversion StagesThe river was diverted in two different stages,

as follows:1st Stage - With the river continuing to flow in its

natural course, and with the protection of a 1st stagecofferdam with crest at El. 88.0 m, the concrete structurewas built on the left bank to place the stop-logs andspillway structure with gates and a lowered sill duringthe river diversion stage.

2nd Stage - through the lowered sill of the spillway.The 2nd stage diversion was undertaken using the

lowered sill of the spillway at El. 76.00 m, consisting ofthe two bays of the radial gates 16.00 m wide by23.68 m total height.

The dam works on the river bed are protected againstfloods of approximately 10-year recurrence intervals (flowof 4,055 m³/s) during the dry season, by cofferdams withcrest at El. 96.00 m (WL at El. 95.04m).

After building the dam works (sill on river bed andabutments) the radial gates were lowered and the sillconcreted.

EquipmentThe radial gate next to the lowered sill was first lowered

to concrete the sill. After this operation, the water flowwas interrupted and the stop-log panels were next insertedin the slots upstream and downstream. Then the gatewas raised in order to concrete the sill to its final position.

The maximum flow foreseen for the closing operationwas in the range of 150-300 m³/s.

Dam and Overflow SpillwayThe dam with an incorporated overflow spillway has a

gravity section in roller-compacted concrete (RCC), theoverflow sill with a total length of around 240 m and crest atEl. 104.00. The stretch in the actual dam tops atEl. 111.00 m, while on the left bank it is 58.00 m and54.00 m in length on the right bank. The maximum height, inthe overflow stretch on the river bed is approximately 33 m.

The dam geometry corresponds to a gravity structure,using the RCC technique to El. 100.00 m and inconventional concrete from there up. The upstream faceis vertical. The downstream face of the non-overflowstretch has a slope of 1V:0.70H below El. 99.90 m, andvertical above this elevation.

On the downstream face, the structure will beconfined by a conventional concrete zone, with averagewidth of 0.65 m raised together with the RCC layers.

The drainage system and inspection of the RCC bodyhas a longitudinal gallery. This gallery is equipped with adewatering system for drained water by gravity andpumping. The main drainage curtain will be carried outfrom this gallery.

The overflow spillway structure is incorporated in thebody of the dam, occupying its entire extension on theriver bed and a large part of both banks. It has a curvingaxis, taking into account the conditions of the dischargingflow downstream. This structure presents a gravity sectionin roller-compacted concrete (RCC), and the overflowspillway extends for around 240 m with the crest atEl. 104.00 m. The height of this structure on the river bedis 33 m. On both banks, the crest of the dam that is notpart of the spillway is at El. 111.00 m

The overflow spillway was designed discharging theflow directly downstream, without a stilling basin as such.

Spillway with radial gateAssociated to the overflow spillway, a spillway with

two bays, controlled by radial gates 16.00 m wide and23.68 m high with the sill at El. 84.00 m, is located onthe left bank.

The radial gates will be used to control the water levelin the reservoir. The gates will be dimensioned to functionby opening or stopping the flow corresponding to themaximum flow and will close under its own weight.

In the chamber of the hydraulic unit, there is anemergency pumping set started by an internalcombustion motor.

The stop-logs for maintenance of these radial gateshave a free span of 16.00 m, sill at El. 76.00 m andheight of 27.60 m.

The spillway was checked for the 10,000 floodcondition with outflow peak equal to 17,958 m3/s, whichresulted in a maximum level in the reservoir atEl. 110.15 m


following structures:• Hollow gravity intake 31.80 m long and 27.00 m high;• Two headrace tunnels around 220 m in length and arectangular-arch cross-section 8 m wide and 10 m high;the armoured stretch has an internal diameter of 10.00 m;• Underground powerhouse, with two Kaplan generators,with maximum height of 40.0 m.


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Headrace CanalThe headrace canal was excavated in rock and has

an approximate length of 40 m and width of 31.80 m onthe canal base.

The canal is designed for a maximum velocity of lessthan 1.50 m/s, considering the canal bottom at El. 87.00 m.

PenstocksThe turbines are supplied through two penstocks

connecting the intake to the powerhouse, approximately220 m in length.

The tunnel geometry has a rectangular-arch cross-section 8.80 m in diameter and 9.75 m in height.Therefore, the arch is 4.40 m high and below the archthe height is 5.35 m. Immediately below the arch, thewidth of the tunnel continues at 8,80 m with 2.10 m inheight. In the remaining 3.25 m, the width of the tunnel isnow 7.80 m.

The penstocks, to meet the operating conditions ofthe turbine, have velocities of 2.50 m/s, and the arch isprotected with shotcrete, with the floor covered withconcrete and the rest of the perimeter unlined rock.

Tailrace tunnelThe return of the turbined flows to the river is through

tailrace tunnels excavated in the rock with lining inshotcrete with steel mesh reinforcement.

IntakeCivil works

The intake in the 14 de Julho HPP consists of a hollowgravity structure fitted with a rectangular-section openingconnecting directly and separately to the power tunnelsthrough a transition (Figure 14).

It was dimensioned for a rated flow of 360.55 m³/sand to operate under a maximum depletion of thereservoir's normal maximum water level of 1.00 m, onlyfor daily flow compensation.

A hydraulically operated fixed wheel gate is installedin the intake for each headrace tunnel to guaranteesecurity for the powerhouse's generation equipment.

Photos 11 and 12 show the dam, intake andpowerhouse during construction.

Figure 14 - 14 de Julho HPP - Water Intake


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Equipment• TrashracksThe six trashracks panels for each water passage

are removable, interchangeable between each other,sliding in the guides installed upstream from the intake.

• Stop-logTo close the intake, during maintenance of the

emergency gate, two stop-logs were planned that areable, together with their fixed parts, to withstand thehydrostatic pressures corresponding to the normalmaximum water level (at El. 104.00 m) and flood level ofthe reservoir (at El. 110.15 m), in normal and exceptionalloading conditions, respectively.

• Fixed wheel gateThere are two fixed wheel gates for each unit to close

under normal conditions. The hydraulic oil centres foractivating the gates consist of two motor-pump groups,one being a reserve.

• Gantry CraneThe gantry crane on the intake crest is used to install

and remove the gates and the stop-logs.

Powerhouse - Civil WorksAccess to the powerhouse is by a tunnel connected

to the main access to the jobsite.It is underground, with two blocks allocated to the

generator units, 20.00 m wide, around 22.40 m in the

Photo 12 - 14 de Julho HPP - Powerhouse

Photo 11 - 14 de Julho HPP - Dam & Powerhouse


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cross-section. The total longitudinal section includingassembly, unload and multi-use areas is 108.90 m.

The loads inside the powerhouse are lifted by overheadtravelling crane, with capacity for 2,000 kN moving over arail track. The galleries for electrical equipment aresituated downstream from the generating unit blocks,where the current restricting reactors, the cubicle for thesupply circuit breaker of the auxiliary services, the generalservice distribution boards, the handling set of 13.8 kVand unit substations will be located.

In the area outside the powerhouse are situated theair intake, drinking water reservoir, the transfer track forthe transformers, step-up transformers, the water and oilseparator tank and the insulating oil tanks. Figures 15,16 and 17 show the plan and sections of the powerhouse.

Powerhouse - PlantTurbines

The two hydraulic turbines are Kaplan with a verticalaxis, spiral steel casing, with rated capacity of51.80 MW, under a rated head of 31.70 m with flow of180.27 m³/s and 94% performance. Rated velocity of171.40 rpm is suitable for direct coupling to three-phasesynchronous generators of 56.1 MVA.Overhead Travelling Crane

An overhead travelling crane for work indoors wasplanned for shifting loads during installation andmaintenance operations of the turbines, generators andother equipment of the plant.

Draft Tube Stop-LogTwo stop-logs for closing a generating unit were

planned for maintenance activities of the turbines. Amonorail was installed for lifting the draft tube stop-logpanels.Step-up Substation

The step-up substation of 14 de Julho is divided intothree sectors: mid-voltage sector, transformation sectorand the 230 kV sector.

The transmission line between the step-up substationof 14 de Julho HPP and the Monte Claro interconnectingsubstation will be in 230 kV, consisting of a three-phasecircuit.

Its total extension is 16,595.03 m, reaching the BentoGonçalves County and Veranópolis, Rio Grande do SulState.

5. CONSTRUCTION

ORGANISATION OF THE JOBSITE ANDINFRASTRUCTURE WORKS

To implement the jobsite, excavations were made insoil, embankments, slope protection, utilities networksand infrastructure services (power network, sewagecollection system, waste collection, laundry, etc.), withpersonnel responsible for operations and maintenance.

The camp facilities of the complex permitted

Figure 15 - 14 de Julho HPP - Powerhouse Plan


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Figure 16 - 14 de Julho HPP - Powerhouse Longitudinal Section

Figure 17 - 14 de Julho HPP - Powerhouse Cross Section


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accommodation for 3,390 employees, five dining roomswith capacity to provide 10,500 meals a day, six medicaldispensaries, sufficient for support of the personnel onthe job. For the three works, recreational areas were builtfor the live-in employees, with games room, satellite TVroom and so on.

Offices were built on the works of the complex, forthe production, quality, occupational and environmentalsafety, engineering and planning, electromechanicalinstallation, administrative and commercial personnel onsite, plus field offices for support to the service fronts.

Industrial facilities for a storeroom, mechanical repairshop, equipment and carpentry yards, fuelling, wash andlubrication station, transport and property security, toserve the civil and electromechanical installation worksfor Monte Claro, Castro Alves and 14 de Julho. Anintegrated environmental education centre was built in14 de Julho HPP, with a nursery for seedlings native tothe region.

Crushing and Concrete Plant FacilitiesThe crushing and concrete plant facilities are divided

as follows: Monte Claro HPP: two crushing plants andtwo concrete plants; Castro Alves HPP: two crushingplants and two concrete plants; 14 de Julho HPP: onecrushing plant and two concrete plants, one of which isspecifically for roller-compacted concrete (RCC)production, for use in the dam of this power plant.

Treatment plants were implemented for treatingsewage from the jobsite installations and works camp.

6. QUALITY CONTROL

Quality Control focusing on the ProjectThe contractor companies Construções e Comércio

Camargo Corrêa S.A., Alstom Brasil Ltda and EngevixEngenharia S.A. agreed on a quality system as well asmanagement activities for its adoption in the sphere ofthe works, services and supplies of the project, alongthe lines of ISO 900 standards.

This quality plan adopted in the complex was certifiedby the company BVQI (certifying agency) in the ISO9001/2000, in the scope of civil works construction andelectromechanical installation of hydropower plants.

7. PROBLEMS FACED DURINGCONSTRUCTION / GROUNDBREAKINGAND SPECIAL SOLUTIONS ADOPTED INCONSTRUCTION

Some problems were found during the constructionof the plants. One of them worth mentioning is theoccurrence of high in situ stresses and rock burst in theunderground excavations of the headrace tunnels ofMonte Claro and Castro Alves HPPs and principally inthe penstocks and main nave of the powerhouse in

14 de Julho HPP. An other problem found as theconstructions went ahead were the constant overtoppingof the cofferdams in the works of Castro Alves and14 de Julho, due to the occurrence of exceptionallygreater inflows than those of the corresponding month ofthe historic period 1940-1997.Shaft excavations

The Raise Boring method was used to excavate theshafts, which is applied to vertical and sloping excavationsin rock, usually tunnels and galleries. This equipmentwas used for the rock excavation of the power tunnels ina vertical stretch of the Castro Alves HPP.

8. ECONOMIC, ENVIRONMENTAL ANDSOCIAL ASPECTS

The characteristics of the 27 environmentalprogrammes that form the Basic Environmental Design(Projeto Básico Ambiental - PBA) originate from theEIA-RIMA (Environmental Impact Assessment-Environmental Impact Report) and address the biotic,physical and socio-environmental aspects.

One of the main programmes worth mentioning is theClimate Condition Monitoring, the principal results ofwhich was to prove that the formation of the reservoirsdoes not cause impact on regional vineyards and winemaking. The monitoring, still underway, also studies theability to forecast the water in the river, in order to achieveefficient operations of the power plants.

Concerning the studies of the water quality, it wasfound that, after forming the reservoirs, theirphysicochemical conditions were maintained, as in thepre-project status. The monitoring of the quality of thewater will continue during the plant operations.

The seismic activity monitoring studies indicated thatthere is no significant influence of the construction of thepower plants and of the new reservoirs on the seismicityof the region.

CERAN proceeds with studies and surveys relatingto the aquatic fauna in the Antas River, since the start ofthe bidding process of the power plants, so that full andcomprehensive knowledge can be gained about theregional ichthyofauna and to establish mitigation andmanagement activities. The main conclusion of thesestudies is that the fish ladder would not be the bestichthyofauna management mechanism in the case of theCERAN Complex power plants. So far, no relevantdamages have been confirmed to the ichthyofaunacaused by implementing the power plants, since therealready were natural barriers that restrict the movementof the ichthyofauna.

With regard to land fauna in the region around thecomplex, the physical integrity of the animals whendeforesting and filling the reservoirs was kept. Fieldrecords include 25 species of amphibians, 13 reptile,202 birds and 45 mammals. Some of these species listed


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as endangered species in Rio Grande do Sul(www.sema.rs.gov.br) are as follows: 9 mammals(7 families) and 3 birds (3 families), with the followingendangered level: 6 mammals - vulnerable; 1 mammal -endangered; 2 mammals - critically endangered; and3 birds - endangered.

One strong point of the project was the low socio-environmental impact compared to the size of thecomplex. In Castro Alves, no family was relocated; inMonte Claro HPP it was necessary to relocate only sixfamilies and 32 families in 14 de Julho HPP. In additionto actual relocation, CERAN followed up these familiesto help in adapting to the new location.

Based on a study with the county secretariats ofeducation, CERAN undertook an extensive program onenvironmental education, which includes capacity buildingof the teachers and instructions to the pupils. Thisprogram covered 88 schools and 175 teachers.

9. PERFORMANCE OF PROJECT

The dams of the CERAN Complex plants were builtin roller compacted concrete (RCC) and are monitoredfor supervision of their displacements, concretetemperature, uplifts in the foundation and seepage flowsin the structure. The following instruments are used forthis purpose: multiple strain gauges, triorthogonaljointmeters, foundation piezometers, thermometers forconcrete and flow gauges.

The powerhouses of the plants were instrumentedusing a triorthogonal jointmeter, rod extensometer;standpipe piezometer and flow gauge.

The results obtained to date show that themeasurements are within the technical designparameters.

10. TECHNICAL CHARACTERISTICS

CASTRO ALVES HPPLocation Nova Roma do Sul, Antonio Prado, NovaPadua and Flores da Cunha - Rio Grande do Sul.Owner CERAN - Cia, Energética Rio das AntasDesign Engevix Engenharia S.A.Civil works construction, electromechanical installationsand supply of transmission lines and substations -Construções e Comércio Camargo Correa S.A:

Supply of turbines, generators, hydro-mechanicalsystems, lifting equipment, electric auxiliary systems

and associated telecommunication systemsAlstom Brasil Ltda: Commercial Generation of

First Operating Unit 28/02/2008

ReservoirUpstream W.L. Normal Min. 239.00 m

Normal Max. 240.00 mFlood Max. 246.36 m

Downstream W.L. Minimum 195.40 mMaximum 209.90 m

Flooded areasFlood W.L. 5.87 km2

Normal Max. W.L. 5.00 km2

Normal Min. W.L. 4.85 km2

River DiversionBy sluicesNumber of spans 4Sluice dimensions 4.00 x 10.00 mDiversion flow (10-year RI - dry) 2,174 m3/s

DamGravity RCCTotal length of crest 350.00 mMaximum height 45.00 mCrest elevation 204.00 m

SpillwayOverflowCapacity 9,011 m3/sSill elevation 240.00 mTotal length 240.00 mEnergy dissipation on river bed

IntakeHollow gravityTotal length 31.80 mNumber of bays 2Fixed wheel gatesWidth 4.50 mHeight 10.00 m

Supply systemHeadrace canalLength 30.00 mWidth 15.00 m

Lined PenstockDiameter 4.00 mNumber of units 3Average length 180.00 m

PowerhouseUndergroundNumber of generating units 3Width of generating unit blocks 12.10 mCross-section of generating unit blocks 17.90 m

TurbinesFrancisRated unit capacity 44.58 MWRated rotation 300.00 rpmReference net head 83.60 mRated unit flow 58.52 m3/sMaximum performance 93.5%


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GeneratorsRated unit capacity 45.54 MVARated voltage 13.8 kVMaximum performance 98.5%Rated power factor 0.9

MONTE CLARO HPPLocation Nova Roma do Sul, Veranópolis

and Bento Gonçalves.Design Engevix Engenharia S.A.Owner CERAN - Cia, Energética Rio das AntasCivil works construction, electromechanical installationsand supply of transmission lines and substations -Construções e Comércio Camargo Correa S.A:Supply of turbines, generators, hydro-mechanicalsystems, lifting equipment, electric auxiliary systemsand associated telecommunication systems - AlstomBrasil Ltda: Commercial Generation of First Operating Unit 29/12/2004.







River DiversionDiversion tunnel associated to spillway with radial gatesand lowered sillTunnel 2Rectangular-arch section 13 x 13 mLength 300 mNo. spillway spans w/radial gates & lowered sill 2Diversion flow (10-year RI - dry) 3,847 m3/s

DamGravity RCCTotal length of crest 250.00 mMaximum height 25.00 mCrest Elevation 148.00 m

SpillwayOverflow associated with 2-bay spillway w/radial gateCapacity 17,038 m3/sSill elevation 148.00 mTotal length 180.00 mEnergy dissipation on river bed

Supply systemHeadrace canalLength 40.00 mWidth 15.00 m

Headrace tunnelRectangular arch 12.50 x 12.50 mNumber of units 1Average length 1,140.00 m

IntakeHollow gravityTotal length 23.80 mNumber of bays 2Stop-logsWidth 4.00 mHeight 12.50 m

PowerhouseShaftNumber of generating units 2Width of generator blocks 22.00 mCross-section of generator blocks 20.10 m

TurbinesKaplanRated unit capacity 67.10 MWRated rotation 150.0 rpmNet reference head 37.75 mRated unit flow 191.38 m3/sMaximum performance 93.5 %

GeneratorsRated unit capacity 72.90 MVARated voltage 13.8kVMaximum performance 98.5 %Rated power factor 0.95

14 DE JULHO HPPLocation Cotiporã, Veranópolis and Bento Gonçalves.Owner CERAN - Cia, Energética Rio das AntasDesign Engevix Engenharia S.A.Construction of Civil Works, ElectromechanicalInstallations and Supply of Transmission Lines andSubstations - Construções e Comércio Camargo CorreaS.A:Supply of turbines, generators, hydro-mechanicalsystems, lifting equipment, electrical auxiliary systemsand associated telecommunication systems - AlstomBrasil Ltda: Commercial generation of first

plant in operation 21/12/2008


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River DiversionUsing the lowered sill of the spillway with radial gatesNumber of bays of spillway w/radial gates 2Diversion flow (10-year RI - dry) 4,055 m3/s

DamGravity RCCTotal length of crest 281.00 mMaximum height 33.00 mCrest elevation 104.00 m

SpillwayOverflow associated with spillway w/2 bays w/radial gateCapacity 17,958 m3/sSill elevation 104.00 mTotal length of overflow stretch 247.00 mDimensions of radial gates 2 x 16.00 x 23.68 m

Supply systemHeadrace CanalLength 40.00 mWidth 31.80 m

PenstockRectangular arch 8.80 x 9.75 mNumber of units 2Average length 220.00 m

IntakeHollow gravityTotal length 31.80 mNumber of spans 2Fixed wheel gatesWidth 4.50 mHeight 10.00 m

PowerhouseUndergroundNumber of generating units 2Width of generating unit blocks 20.00 mCross-section of generating units 22.40 m

Kaplan turbinesRated Unit Power 51.80 MWRated rotation 171.40 mNet reference head 31.70 mRated unit flow 180.27 m3/sMaximum performance 94%

GeneratorsRated Unit Capacity 56.10 MVARated voltage 13.8 kVMaximum performance 98.5%Rated power factor 0.9


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CASTRO ALVES HPP

Powerhouse - Electromechanical Gallery

Construction of the Dam

Overflow Dam during Construction - View from Downstream

Overflow Dam during Construction - View from Upstream

Powerhouse during Construction

Headrace Tunnel during ConstructionRock Trap and Surge Chamber


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MONTE CLARO HPP

Spillway -View from Upstream

Intake Structure

Overflow Dam and Spillway at the End of Construction - View from Upstream


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MONTE CLARO HPP

Powerhouse and Switchyard

Powerhouse in the Construction Stage

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14 DE JULHO HPP

Excavation of the Powerhouse - Treatment of the Rock Wall

Spillway and Radial Gates during the Diversion Stage -View from Downstream

Diversion through the Spillway

Power Tunnel in the Construction Stage

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