The island state of Sri Lanka has quite a long history of hydropower utilisation. This is one of the reasons why the quality of hydropower machines from the alpine region are highly appreciated here.
For years, Upper Austrian hydropower specialist Global Hydro Energy has been contributing to the high reputation of Austrian technology on the Sri Lankan hydropower market. With 19 installed hydropower plants under its belt, Global Hydro is now one of the industry’s leading providers of hydropower solutions. The most recent project was completed last year in the central province of Matale on the river Ganga. Global Hydro not only provided the electromechanical equipment for the new low-head power plant, but also installed the entire hydraulic steelwork. With the handover to the customer, the project was successfully completed October 2014.
On Sri Lanka, hydropower constitutes the most important form of electrical energy. Almost half of the entire electrical energy in the national grid is supplied by the hydropower plants that are distributed across the entire island state. Although the market for large-scale hydropower has by now reached its limit due to the lack of available sites, the Indian Ocean state with its 103 rivers still offers a sizeable growth potential in terms of small hydropower. Recently, the Sri Lankan government has made it quite clear that they intend to exploit that potential. A new law was passed already a few years ago that allows private enterprises to build power plants as well. One of the firms taking advantage of this opportunity is Ross Hydro Power, whose owner is in the concrete and tiling business. Since 2010 Ross had been planning a small-hydropower plant on the Suda Ganga river in the central Sri Lankan province of Matale – and obtaining the required planning permission.
Familiar hydropower terrain for Global Hydro
The site was not virgin territory as far as hydropower projects was concerned. “Previously, there used to be a small power station there, around a hundred years old, with just one turbine. However, none of the original structures could be salvaged for reuse in the new project,” explains project manager Thomas Kuffner of Global Hydro. For him and his team, the location was anything but “terra incognita”. After all, a few years earlier Global Hydro had been supplying turbines for hydropower plant Rajjammana some 15 km downstream. As the contract for the electromechanical equipment and hydraulic structures had been awarded to the Upper Austrian hydropower specialists already in March 2012, the first excavators arrived at the site already in June. However, the first year of construction work was marked by a considerable setback: In December 2012, a once-in-a-hundred-years high-water flooded the entire construction site. Spilling over the riverbed, the Suda Ganga quickly destroyed part of the existing basic structures, leaving damage, increased construction costs and a delayed project schedule in its wake.
Turbine specialist proves hydraulic steelwork engineering competence
After this incident, the construction project was spared any further catastrophic events, so that the power plant facility slowly began to take shape in 2013. In March 2014, it was finally time for the Global Hydro engineers to step up to the challenge – a challenge that would test them to their limits. One reason for this was the climatic the conditions, another was the fact that with this project the team was venturing into new hydraulic engineering territory. After all, the contract included not just the turbines, generators and gearing units, but also the coarse and fine racks, intake gates, trash rack cleaners and flushing gates. Both the construction and on-site installation requirements posed new challenges to the Global Hydro engineers and technicians – a test of their abilities, however, that they passed with flying colours.
“Although Sri Lanka boasts an extensive hydropower infrastructure, it’s still quite difficult to find the proper heavy-duty equipment that’s required for installation work. This was an issue, especially when we were supposed to install the hydraulic steelwork engineering equipment,” says Thomas Kuffner, explaining why this can sometimes cause project delays in the Far East. “Lack of appropriate tools or equipment often is a real problem in Sri Lanka,” he says. Getting the gate operating mechanism to the construction site was not easy either. Since it had to be transported in its pre-assembled state, a heavy haulage vehicle was needed, and arranging for one turned out to be a real challenge.
Despite all these obstacles, the installation and commissioning work went smoothly without any further incidents. On September 16 last year, the two Kaplan open flume turbines were spun up for the first time. With the trial operation in full swing, hydropower project Suda Ganga River entered its final phase. Conceptually, the facility is a low-head power station with a maximum flow capacity of 60 m3/s. By way of a lateral intake, the water is split into two non-pressure channels and flows past the fine racks to the turbine chamber. The generously dimensioned power house is home to two Kaplan open flume turbines, which are designed for a maximum head of 9.6 m and a design flow rate of 30 m3/s each. The nominal speed of the turbines is 177 rpm. An Eisenbeiss gearing increases this rotational speed to an operating speed of 750 rpm. This is the required drive speed for the synchronous generators by Hitzinger, which have a nominal capacity of 2.9 kVA. Both the generators with their gearing assembly and the hydraulics with the regulating mechanism were included in the scope of Global Hydro’s delivery.
A well-established brand also in the Far East
For the constructors, HPP Ross marked their first hydropower project so far. For Austrian-based hydropower specialist Global Hydro, it was the nineteenth project of this type in the Far Eastern island state. This makes the Upper Austrian provider the undisputed market leader in the Sri Lankan hydropower market. Where market performance is concerned, is not just the high quality of the equipment that sets Global Hydro apart, but also their superior reliability and flexibility, which has enabled their success in this local hydropower market. The new hydropower plant Ross may serve as a case in point.