| The Solina pumped storage plant is located in the heart of the Polish Bieszczady Mountains. The Solina reservoir - the biggest artificial lake in Poland - attracts a lot of tourists and the Solina dam is of strategic importance owing to its scenic or natural qualities, as well as to its potential as flood control facility.
Modernization began in 2000. Being partially pumped-storage and partially conventional hydro, Solina is a unique facility, not only in terms of scenic beauty, ecology and flood control, but also because of its key asset: the potential to produce inexpensive energy.
Solina's Unit 1, modernized and upgraded, was commissioned in 2001. Unit 2 was commissioned in January 2002. Unit 3 began operation in December 2002. Upon completion of the replacement of Unit 4 in July 2003, Solina's capacity went up from originally 136 to 200 MW.
By means of thorough inspection of the two turbine-generator units, backed by Voith Siemens Hydro’s unique computational assessment tools and by fluid dynamics analysis (CFD analysis), the optimization potential, outage time and pertinent costs were identified, thus giving the customer a clear idea of the benefits of rehabilitation prior to signing the contract.
In terms of execution, the most crucial engineering challenge was the optimization of the two vertical-shaft Francis turbines, each with a limited output of 48 MW, installed in 1967. A completely new runner, fitting into the existing wheel case, has been developed. Whereas normally a performance increase of approx. 15 to 30 % would have been achieved, the Solina turbines, with unchanged speed ratings, but a discharge increase from 127 to 139 m³/s, were upgraded to 73 MW as contractually agreed.
This huge increase in performance of more than 50 % and the simultaneous elimination of vibration problems in the partial load range was the result of a precise realignment of the turbine guide bearing and the installation of a stabilizing air system. The Gdansk-based Turbo Institute had established that the extent of vibration-free operation actually exceeded the contractually agreed range. In addition, the generators had been upgraded, the turbine control system had been changed to digital technology, the pressurized air-oil supply system had been adapted, a thrust bearing lifting device had been installed, and the excitation equipment had been replaced by a static one.
Stringent time management allowed the completion of the refurbishment a solid two weeks ahead of the contract deadline, even though cracks in the turbine shaft that were discovered after the dismantling of the second machine required a new 20-ton shaft to be supplied in record time.
Without any environmental impact, the power plant’s non-polluting energy production has been substantially increased, its operational range has been widened and its lifetime has been extended by at least another 30 years. Consequently, the Solina HEPP rehabilitation project has been a full success for everyone involved.
Once the two other, smaller, reversible machines have been upgraded, an estimated total annual energy increase of 93 GWh (i.e. from 137 to 230 GWh), including peak energy supply, will be achieved. After the completion of the project, Solina hydropower plant will be the largest and most modern hydropower plant in Poland. |
