Research output: Chapter in Book/Report/Conference proceedingConference contribution


In a changing energy market with decreasing energy prices, energy suppliers try to ensure their yield with their existing hydro power plants. One possibility to raise the annual energy earnings is not only to increase the power output but also the availability and flexibility of an existing power plant. Most of the older power plants – in particular storage power plants – are not designed for such operating modes – especially not for rapidly changing and fluctuating load.
As many plants operated today were constructed decades ago, the original plant design was based on operating conditions which are completely different to the ones actually required. To prove the ability for higher flexibility in power generation, detailed investigations of the power water way, especially surge tank limitations, are necessary. Since the main constructive infrastructure cannot be changed or just in a limited way, only limited additional power generation is possible. The higher the demand for an increasing power output, the higher are the limitations in operational flexibility. An overflow of the surge tank must be prevented in any possible operational or exceptional scenario of the power plant. On the other hand a ventilation of the headrace by means of an ineligible empty surge tank must not occur during operation.
Flexible operation induces a highly transient fluid flow in the headrace and especially the surge tanks of high head hydro power plants. In the planning phase of activities to increase the power output and/or the flexibility, a reliable prediction of the transient plant behaviour and especially the surge tank performance in unsteady load cases - such as periodic machine starts and stops or switching load cases - is necessary.
Modern techniques in numerical simulation methods provide the only feasible possibility to accurately calculate the occurring mass oscillations and pressure pulsations as well as for the optimization of the transient behaviour. Commercial software-packages for water hammer simulations usually do not provide numerical models for a realistic calculation of complex components like surge tanks, hydraulic turbines or emergency closing valves in a high head hydro power plant. But especially these components need to be modelled correctly in order to get a significant and reliable solution. A validation of the numerical models by means of onsite measurements at the existing hydro power plant yields additional confidence for a safe operation after the power increase.
The present paper shows the successful application of custom designed numerical models for surge tanks and hydraulic turbines in the course of waterhammer analysis. An executed example of a power plant with increased power output and flexibility is demonstrated.
Original languageEnglish
Title of host publicationBook of Full Papers, Symposium Hydro Engineering, ICOLD 2018
Place of PublicationGraz
PublisherVerlag der Technischen Universität Graz
Number of pages11
ISBN (Electronic)978-3-85125-620-8
Publication statusPublished - 1 Nov 2018
EventWorld Congress ICOLD 2018 - Wien, Austria
Duration: 2 Jul 20183 Jul 2018
Conference number: 26


ConferenceWorld Congress ICOLD 2018
Abbreviated titleICOLD 2018

Fields of Expertise

  • Sustainable Systems

Treatment code (Nähere Zuordnung)

  • Application

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