Speed Rise and Pressure Rise in Pelton

Ask the instructor.

That question is best asked of the hydrogenerator's manufacturer, there are too many variables to give a simple answer. For starters, it depends upon the load, the machine's inertia, physical dimensions of the waterway, the governor and the rate at which the flow control valve can be closed.

If this is a home-brew setup then you may have to resort to experimentation unless you're real comfortable with differential equations or dynamic simulation programs like MatLab or MathWorks.

Dear Anonymous Poster No.1,

You have NOT mentioned the Percentage of Load Rejection and its Duration. Is it instantaneous or gradual and prolonged time in Seconds. This aspect plays a vital role. If it is instantaneous then the Pressure build-up and Speed Build-Up will be very FAST, and WATER-HAMMER will be INTNSIVE and Surge tank should accomodate the flow.

If Load Rejection is small, by Percrcetage wise, the Water-Hammer will be SMALL, the Pressure build-up and Speed Build-Up will be SLOW.

The Points below can be taken as Supplementing the Posting No.2, above i.e., by Mr.RAMConsult -

Water is INCOMPRESSIBLE FLUID, hence the Pressure build-up will be very high due to Inertia of Flowing Water. speed buid-up depends on Inertia of revolving mass of the turbine and generator rotor.

Also speed build up depends upon the speed of the sensing by the governor.

DHAYANANDHAN.S

Dear Anonymous Poster No.1,

You have NOT mentioned the Percentage of Load Rejection and its Duration. Is it instantaneous or gradual and prolonged time in Seconds. This aspect plays a vital role.

If it is instantaneous then the Pressure build-up and Speed Build-Up will be very FAST, and WATER-HAMMER will be INTNSIVE and Surge tank should, reduce the Pressure Build-Up with in the Turbine In-Let Pipe and accomodate the flow.

If Load Rejection is small, by Percrcetage wise, the Water-Hammer will be SMALL, the Pressure build-up and Speed Build-Up will be SLOW.

The Points below can be taken as Supplementing the Posting No.2, above i.e., by Mr.RAMConsult -

Water is INCOMPRESSIBLE FLUID, hence the Pressure build-up will be very high due to Inertia of Flowing Water. Speed Buid-uUp depends on Inertia of revolving mass of the turbine and generator rotor.

Also speed build up depends upon the speed of the sensing by the governor.

DHAYANANDHAN.S

NOTE: Please ignore my earlier Post No.3, since there was typing error and time lapsed before correction.