Avbördningskapacitet för Traryd kraftverk

Sammanfattning

Sydkraft Vattenkraft AB owns and operates the Traryd hydropower plant,

located in the river Lagan in the southern part of Sweden. The gravity dam

is classed according to RIDAS guidelines (Hydropower Industry Dam Safety

Guidelines) as a class 1B dam. This means that the dam must discharge a

class 1-flow which has a return period of 10 000 years. The inflow into the

dam has been calculated in an earlier report to 495 m3/s, with a waterline

at an elevation of 126, 3 meters above sea level. The gravity dam has a

discharge system with two rectangular weirs, which results in a smaller

discharge than the necessary 495 m3/s.

The discharge capacity is normally calculated with theoretical

relationships, which include discharge coefficients for various conditions.

Characteristic values are given in the literature. For better estimations

numerical simulations or laboratory flume experiments can be carried out.

After some considerations, it was decided to perform a laboratory model

study in scale 1:66.

The modelling was initially used to estimate the discharge capacity and

secondly, to test modifications of the weir inflow. The experimental

modelling resulted in a discharge capacity of 452 ± 14 m3/s when the surface

level was 126, 3 meter above sea level. This can be compared to the results

of the theoretical calculation 462 m3/s. Furthermore, including the use of a

reconstructed old weir increased the discharge capacity to 509 ± 20 m3/s.