Bulb hydrogenerators for low-head hydro plants up to 83 MVA
Bulb hydrogenerators for low-head hydro plants rated above 80 MVA with a voltage of 3.3 to 13.8 kV. They work together with bulb Kaplan turbines and are cooled by a closed circuit into the river water. Used on lowland rivers and navigation dams.
- Output
- above 80 MVA (Jirau 83.33 MVA; Santo Antonio 82.25 MVA)
- Voltage
- 3.3; 6.6; 11; 13.8 kV
- Cooling
- closed circuit with heat release into the river water; compressed air for powerful and high-speed machines
- Bearings
- 2 supports (guide + combined guide/thrust), 3 supports for large machines
Price, availability and lead time on request. We help with analogue selection, customs clearance and delivery.
Description
Bulb hydrogenerators are installed inside a streamlined bulb in the flow passage of low-head hydro plants, paired with horizontal bulb Kaplan turbines. This arrangement is used on lowland rivers, navigation dams and cascades with a head of up to 30 m and large flows. A bulb unit has a higher efficiency at full load and a greater throughput than a vertical Kaplan, and construction costs less.
The manufacturer has supplied bulb generators since the mid-1950s. As unit ratings grew, the rated voltage rose too: from the initial 3.3 and 6.6 kV to 11 and 13.8 kV on powerful machines, and the latest designs exceed 80 MVA. Cooling systems have evolved from separate heat exchangers to maintenance-free closed circuits that release heat directly into the river water around the bulb. For very powerful and high-speed machines, compressed air is additionally used for better heat removal.
Most units have two bearing supports, with a guide bearing near the cantilever runner and a combined guide/thrust bearing on the support column behind the generator. The bearing systems of horizontal machines are designed for the reverse axial force during load rejection. Three-bearing layouts are provided for some high-output machines. The generator and turbine operate as a single horizontal unit in the flow passage, and heat from the machine is transferred to the closed circuit and then to the river water washing the bulb.
References include 13 units of 75.55 MW / 82.25 MVA each for the Santo Antonio hydro plant and 10 units of 76.5 MW / 83.33 MVA each for the Jirau hydro plant (Brazil, Madeira River), four hydro plants on the Ohio River with 11 units and a total of 321 MW / 357 MVA, bulb units of 36 MW / 39 MVA for Baguari, 33 MW / 33.7 MVA for Bailongtan, 23.7 MW / 21.6 MVA for Chashma and 17.4 MW / 20 MVA for Kirchbichl. For small hydro plants, similar generators are supplied with pit turbines through a gearbox and with S-type turbines. Applications cover run-of-river plants on lowland rivers, navigation lock dams and modernization of bulb stations.
Technical specifications
| Output | above 80 MVA (Jirau 83.33 MVA; Santo Antonio 82.25 MVA) |
|---|---|
| Voltage | 3.3; 6.6; 11; 13.8 kV |
| Cooling | closed circuit with heat release into the river water; compressed air for powerful and high-speed machines |
| Bearings | 2 supports (guide + combined guide/thrust), 3 supports for large machines |
| Design | horizontal, vertical bulb |
| Deliveries | since the mid-1950s |
Request a price and lead time
Bulb hydrogenerators for low-head hydro plants up to 83 MVA. We reply within one business day.
Or email sales@usk.ua or call 044 339-50-20.
Questions and answers
What output do bulb generators have?
The latest designs exceed 80 MVA. The units for Jirau are 83.33 MVA, for Santo Antonio 82.25 MVA.
What voltage are bulb generators built for?
3.3 and 6.6 kV in the early designs and 11 and 13.8 kV on powerful machines.
How many bearing supports do the bearing assemblies have?
Most machines have two supports, with a guide and a combined guide/thrust bearing. Three supports are provided for some high-output machines.
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