Pelton turbine minimum flow/power

Good morning everybody.

I need your expert advices.
We are retrofitting an hydro power plants with three Pelton turbines that drive 8 MW alternators.
Historically, the turbines cannot be operated below 2 MW. But I cannot find any manufacturer documents that support this figure.
I know that the minimum power has to do with the water speed in the nozzles that, if not limited, can be harmful to the gear.
What is a typical minimum flow figure for a Pelton turbine nozzle?
Somebody told me that we should always operate above 25% of the nominal power. It matches the 2 MW figure on an 8 MW turbine. But is the concept applicable to other Pelton turbines?
I am looking forward to hearing from you.

Best regards.

Carlos Melim
 
Carlos... While not an expert, I do teach a Renewable Energy course in which The Pelton is discussed with some detail. As you stated the energy of the water-jet impinging on a number of buckets mounted on the periphery of a wheel is eventually converted to electrical energy! Simple, but if the jet’s energy is altered, resulting in mis-direction, the buckets (over time) could be damaged!

You said, historically, minimum operation is 2MW (25%). “Someone” asserted, “always above 25%”! The advice given you is Rule of Thumb (ROT), and, if you can’t corroborate it there is the question of risk!

Now, my advice, since you asked… The actual value can’t be calculated using name-plate data! So, question the mfg! If unavailable, then question other mfg’s, or others you know experienced in field!
Good Luck, Phil Corso
 
Carlos... While not an expert, I do teach a Renewable Energy course in which The Pelton is discussed with some detail. As you stated the energy of the water-jet impinging on a number of buckets mounted on the periphery of a wheel is eventually converted to electrical energy! Simple, but if the jet’s energy is altered, resulting in mis-direction, the buckets (over time) could be damaged!

You said, historically, minimum operation is 2MW (25%). “Someone” asserted, “always above 25%”! The advice given you is Rule of Thumb (ROT), and, if you can’t corroborate it there is the question of risk!

Now, my advice, since you asked… The actual value can’t be calculated using name-plate data! So, question the mfg! If unavailable, then question other mfg’s, or others you know are experienced in field!
Good Luck, Phil Corso
 
Hello Phil.

Thanks for your reply. The turbine is 25 years old and its manufacturer is no longer in the business.

My main concern is not the damage on the buckets but the ones on the nozzle as you can see in the picture attached.

The unsupported 25% rule of thumb is very questionable.

I will try to contact companies like ANDRITZ and VOITH to get some more information.

Do you have any other contacts I should address?

Again, thanks for your reply and have a nice Christmas.

3CC369AB-68CE-4C19-A8BA-9CE1AFC389A0.png
Carlos Melim
 
Hello Phil.

Thanks for your reply. The turbine is 25 years old and its manufacturer is no longer in the business.

My main concern is not the damage on the buckets but the ones on the nozzle as you can see in the picture attached.

The unsupported 25% rule of thumb is very questionable.

I will try to contact companies like ANDRITZ and VOITH to get some more information.

Do you have any other contacts I should address?

Again, thanks for your reply and have a nice Christmas.

View attachment 44
Carlos Melim
Carlos... I suggest contacting Hydro-Service organizations.
 
Carlos… is your project associated with our Government’s Hydropower Vision study? Following is a quote from José Zayas Director, Wind and Water Power Technologies, USA Dept of Energy:
“Hydropower Vision highlights the great potential of untapped hydropower resources across the United States, finding that U.S. hydropower could grow from 101 gigawatts (GW) of combined generating and storage capacity to nearly 150 GW by 2050 --- with more than 50% of this growth realized by 2030. Growth under this scenario would result from a combination of 13 GW of new hydropower generation capacity (upgrades to existing plants, adding power at existing dams and canals, and limited development of new stream-reaches), and 36 GW of new pumped storage capacity.”
 
Good morning Phil Corso.
I’m from Portugal, Madeira Island.
I work for the island utility and we have eight hydro power stations, all with Pelton turbines.
We are retrofitting two of those and that’s why I’m searching for informations on the minimum operational power of a turbine generator.
 
Carlos... Congratulations... Saw your facilities on You-Tube. Interesting fact... largest in Europe, plus includes a pumped-storage plant!
I'm surprised you can't get advice from Alsthom!
Phil Corso
 
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