Mascarenhas de Moraes Plant - 476 MW


Credit: AC Júnior


The history of the Mascarenhas de Moraes Plant, previously called Peixoto, dates back to 1947, ten years before FURNAS was first created, at a time when the Companhia Paulista de Força e Luz (CPFL) generating capacity was threatening to run out. Dam construction was based on studies carried out across a 59,600 km² drainage basin, indicating the dam would provide a number of benefits, such as regulating the Grande River’s outflows.

In 1950, CPFL was granted the concession to build a hydroelectric plant on a site near the city of Ibiraci. Seven years later, two 40 MW units began operating. This was the first large-scale power plant built on the Grande River.

The Mascarenhas de Moraes plant is located between two major energy complexes, built between the Furnas (upstream) and Luiz Carlos Barreto de Carvalho (downstream) Plants. Later on, when the Furnas Plant began regulating the Grande River's flow, this means more units could be deployed as the Peixoto Plant reached its final capacity of 476 MW, with ten generator units, in 1968.

In December of the same year, Peixoto was renamed the Usina Marechal Mascarenhas de Moraes. FURNAS only began running the plant on August 1, 1973, following a decision by Eletrobras.


Technical Data


Dam

  • Type: arch and gravity
  • Development at the crown: 600 m
  • Elevation at crown: 669.12 m
  • Total volume: 800 thousand m³


Reservoir

  • Normal operating level: 666.12
  • Maximum flood level: 666.92
  • Level of expropriation: 668.62 m
  • Minimum operating level: 653.12
  • Flooded area: 250 km²
  • Total volume: 4.04 billion m³
  • Usable volume: 2.5 billion m³


Water Intake

  • Sliding gates
  • Quantity: 10
  • Water height on sill: 22 m
  • Width: 7.08 m
  • Height: 6.15 m
  • Manufacturers: 1 to 3 - Paceco (USA) / 4 - Monarch (USA) / 5 to 10 - Torque (Brazil)


Spillway

  • Maximum Discharge: 9,350 m³/s
  • Segmented gates
  • Quantity: 11
  • Width: 10.67 m
  • Height: 12.98 m
  • Radius: 10 m
  • Manufacturer: Paceco (USA)


Ancillary spillway

  • Maximum Discharge: 3.1000 m³/s
  • Segmented gates
  • Quantity: 2
  • Width: 12 m
  • Height: 16.50 m
  • Radius: 16 m
  • Manufacturer: Bardella S.A.


Powerhouse

  • Type: semi-sheltered
  • Size: 210 m x 25 m
  • Generator units: 10
  • Rotation: 128.6 RPM (units 1, 2, 5, 6, 7 and 8) / 138.5 RPM (units 3, 4, 9 and 10)
  • Rated capacity: 40 MW (units 1 and 2) / 48 MW (units 3 and 4) / 49 MW (units 5, 6, 7 and 8) / 52 MW (units 9 and 10)


Turbines

  • Type - Vertical axis Francis
  • Rotor diameter: 3.911 m (units 1 and 2) / 3.947 m (units 3 and 4) / 4.013 m (units 5, 6, 7 and 8) / 3.950 m (units 9 and 10)
  • Manufacturers: 1 and 2 (Dominium/Canada) / 3 and 4 (Morgan Smith/USA) / 5, 6, 7 and 8 (W.Stell/USA) / 9 and 10 (MEP/Brazil)


Generators

  • Frequency - 60 Hz
  • Terminal voltage: 13.8 kV
  • Manufacturers: 1 and 4 (Westinghouse/USA) / 5, 6, 7 and 8 (General Electric/USA) / 9 and 10 (Brown Boveri/Brazil)
  • Transformers: 24 (operation + back-up)
  • Type: single-phase / three-phase
  • Total operating capacity: 797.92 MVA
  • Transformation ratio: 13,8 / 345 kV / 13,8 / 138 kV
  • Manufacturer: ABB / Westinghouse / GE / Alsthon