NVKS_presentation_spring

Background

Machine Hall, Tonstad Hydropower Plant

Asymetric throttle, Reisseck II

Tonstad power plant is the largest power plant in Norway regarding to annual energy

production. The water conduit was originally designed for 640 MW, and the latest addition of

320 MW has resulted in problems related to hydraulic transients. One of the major problems

are related to the amplitude of mass oscillations in the three surge tanks. It is especially

a concern that the water level in the surge tanks may be drawn down into the tunnel and

release air in the waterway. By installing throttles in the surge tanks, it is possible to reduce

the amplitudes.

Surge Tank Throttle

A surge tank throttle is a construction that

reduces the flow area in the shaft of a surge

tank to induce a great singular loss. The loss

will contribute to better regulation stability by

faster dampening the mass oscillations in the

surge tank. Different configurations can be

used to achieve different losses in upwards and

downwards direction. An asymmetric throttle,

from Reisseck II in Austria, is shown below.

Thesis Objective

The objective of the thesis is to utilize a numerical model

of Tonstad to find the optimal throttle losses for the surge

tanks. A suggestion of throttle configuration is to be made,

along with an economic analysis of the selected solution.

Master Thesis

Department of Hydraulic and

Environmental Engineering

Design of a Surge Tank

Throttle for Tonstad

Hydropower Plant

By Daniel Gomsrud

Lia

Kaspar Vereide