Três Irmãos Plant - 807.5 MW


The Novo Oriente consortium, owned by FURNAS (49.9%) and the Fundo de Investimento em Participações Constantinopla (50.1%), won the concession for the Três Irmãos Hydroelectric Plant (SP), which was organized by the National Electrical Energy Agency (Aneel) in February 2014. The HEP started operating in 1993. The concession will last 30 years. The plant has 05 (five) x 161.5 MW Generator Units and a total Installed Capacity of 807.5 MW.


Location

The Três Irmãos HEP is located at the Tietê River basin (in a stretch called "Baixo Tietê"), 28 km upstream from the river’s mouth in the city of Pereira Barreto (SP), bordered by Andradina (SP), on Highway SP-563, km 15 (interconnecting SP-310 with SP-300). The reservoir links with the Nova Avanhandava HEP, as they are on the same river. Downstream, it flows into the Engenheiro Souza Dias (Jupiá) HEP reservoir, also on the Tietê River, and subsequently into the Paraná River, where it links with the Jupiá HEP. Water course: Tietê River.

An artificial channel built by CESP and inaugurated in 1990 interconnects the reservoirs at Ilha Solteira and Três Irmãos, working as a "communication channel", transferring flows both ways. This means the waterway can be used for navigation, integrated hydraulic operation of both reservoirs and helps control floods both on the Tietê Waterway and the Paraná Waterway, without the need for a floodgate at Ilha Solteira.


General Features

The plant has 05 (five) x 161.5 MW Generator Units and total Installed Capacity of 807.50 MW. The hydrographic basin covers an area of 69,900 km². The NAV-TRI intermediate basin covers 7,600 km² and there are no significant affluents along this section. The reservoir covers 757 km² at normal maximum level and 785 km² at its absolute maximum level, with flows from HEU Nova Avanhandava and the Ilha Solteira reservoir through the Pereira Barreto Interconnection Channel, which works in both directions.


Technical Data


Upstream levels

  • Maximum level: 328.4 m
  • Normal maximum level: 328 m
  • Normal minimum level: 323 m
  • Minimum operating level: 325.4 m


Downstream levels

  • Full absolute maximum NA level: 284.75 m
  • Maximum NA level: 282.4 m
  • Normal minimum level: 279 m


Flow characteristics

  • Average MLT flow (1931-2010): 768 m³/s
  • Apparent turbine flow: 2,040 m³/s


Construction characteristics

  • Gravity-type dam: soil and concrete
  • Width at crown: 3,640 m
  • Level at crown (concrete): 331.4 m
  • Level at crown (soil): 332.4 m
  • Concrete dam width: 480 m
  • Maximum height: 62 m


Hydroelectric Plant characteristics

  • Maximum spillway outflow: 9,500 m³/s
  • Maximum historic outflow: 4,542 m³/s (2011)


Spillway

  • Surface spillway: 4 14x18 m spans
  • Segmented gates
  • Spillway floor elevation: 310.5 m


Volume characteristics

  • Dead volume: 10,000 hm³
  • Usable volume: 3,450 hm³
  • Full flooding volume: 350 hm³
  • Total volume: 13,800 hm³