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- Model VLH - Hydraulic Turbine
Model VLH - Hydraulic Turbine
Hydraulic turbines are bulky by nature. Indeed, to generate even relatively moderate output (on the order of some hundred kW) under heads lower than 3 m, turbine flow rates can exceed 10 m3/s. This results, for water supply works, in large civil engineering structures proportioned to the collected flow rates.
To make their equipment more competitive, hydraulic turbine constructors have always endeavoured to optimize their product by increasing performances, in particular by a permanent research oriented towards the decrease of the runner diameters. This runner diameter decrease has led to water intake and outlet structures of a dimension such that their economical implementation is impossible when the head is too low.
The basic idea of the VLH concept goes against this tendency by aiming at decreasing, as much as possible, intake and outlet structures by increasing the size of the turbine runner diameter and by integrating therein a self-supporting structure which ensures all the functions of a conventional facility.
The VLH incorporates the following functions:
- Standardized Kaplan turbine with 8 adjustable blades according to the upstream level and to the flow.
- Self-supporting structure enabling complete factory assembly and very fast mounting or dismounting.
- Slow direct-drive variable-speed permanent-magnet generator.
- The VLH stops by closing its blades. VLH installations do not require upstream gates to stop the unit.
- Distributor used as a protection grid.
- Built in rotating trash rake cleaner.
- Electronic full output frequency converter.
- Integrated electronic control equipments managing the turbogenerator unit and the power electronics equipments.
- Withdrawal device enabling taking the unit out of the water for maintenance.
VLH is able to operate with very low heads, from 1,5 to 4,5 meters.
The use of the VLH turbine allows a sensible reduction of civil works costs. The quantity of concrete is reduced and no external buildings are necessary.
Tests executed on eels, salmons, trouts and other species demonstrate unprecedent fish friendliness .
VLH displays submerged turbine and generator. There is no significant environmental impact. The turbine is noiseless and there are no vibrations.
It will be able operate fully automatically, thus without connection to the electrical grid.
A standard product distributed on different sizes. The price is affordable. Low implementation and delivery schedules.
Thanks to the permanent magnets generator with variable speed, the VLH turbine allows a very good performance even with wide head variation.
Since the VLH concept only addresses a relatively narrow range of heads and flow rates, it is perfectly well adapted to being totally standardized.
Range of products
A range of machines provided in 5 diameters (3,150-3,550- 4,000- 4,500- 5,000 mm) has thus been designed.
Net head range
The net head range addressed by the VLH concept extends from 1.5 to 3.4 m. (up to 4,5 m in customised reinforced version).
The reinforcing of the supporting structure has enabled to bring the acceptable net head up to more than 4.5 m for the three smallest models in the range.
Flow range
The range of flow rates of the equipments extends from 10 to 27 m3/s, and the addition of several units on a same site enables considering very high total equipment flow rates.
Power range
This results in a range of power per unit from 100 to 500 kW (at the network level). It is estimated that below 100 kW, the expected profitability will not be achieved, and the studies performed up to now demonstrate that above 500 kW, it is more profitable to install several smaller machines rather than a single large one.