www.iteco.ch/Renewable Energy & Water/Project Selection/SHPP Trin Mulin - Switzerland

Tailor-made equipment for Trin-Mulin Small Hydropower Plant

Renovation of the hydroelectric equipment and power house for Trin-Mulin HPP

When the generator failed at the end of 2003, the Community of Trin, the owner of Trin-Mulin HPP, decided to replace the antiquated machinery and fully rehabilitate the old power station to eliminate the need for costly maintenance. ITECO was commissioned to manage the project.

Tailor made solution

A comprehensive feasibility study carried out by ITECO showed that the optimal solution based on two identical Pelton turbines would best fulfil the owner's requirements, namely:

  • able to quickly adjust to change in the load demand in the power net (for example when the ventilation fans in the nearby road tunnel start to operate) so that peaks can been smoothed and costs saved;
  • able to operate with only small quantities of water (relevant in the dry winter months) to operate efficiently without continual on-off switching operations;
  • robust construction but at the same time allowing easy maintenance access to the machines;
  • high availability due to the use of two independently operated machines; and
  • optimised use of the available floor space in the powerhouse

Alternatives studied and the optimal solution

 

 

Control and connection to the regional power grid

The machines are fitted with numerous control and protective devices to facilitate fully automated and secure operation. The control mechanism provides optimal efficiency, balances the load on each machine and optimises use of the 2,500 cubic metrecapacity undergroundstorage reservoir. Manual intervention, either via computer or directly at the switching cabinet, is possible at all times. The link between the control systems of Trin-Mulin and the neighbouring Flims Electric AG power station permits permanent monitoring to be carried out.

Optimised rearrangement of powerhouse The machine hall and the discharge channels were totally rearranged but the structure of the building remained nearly untouched. Only four months after the start of work the first power was produced. Great importance was set on functional and user friendly construction details:

  • Sound absorbing walls and ceilings
  • Separate control room with view to the machines
  • Low maintenance flooring using synthetic material
  • Overhead crane with maximised coverage of machine hall




Project main data

Design Flow 1.4 m3/sec
Gross Head 140 m
Average Annual Production 5.8 million kWh
Installed Capacity 1.5 MW
Equipment Two identical 750 kW Pelton turbines each with 2 injectors. Synchronous, air/water cooled generator


Project duration

  • Beginning of the planning and design work: June 2003
  • Commencement of construction: August 2004
  • Start of new operation: March 2005
  • Total cost of the refurbishment and upgrade: SFr 2,200,000

Location

The power plant is located in Trin-Mulin, next to the Kantonsstrasse and directly at the confluence of the Turnigla and the Trimosa streams, the coordinate point is 745.100/188.650 and is shown on the map.