Influence of the Hydraulic System Layout on the Stability of a Mixed Islanded Power Network

  • Christian LandryEmail author
  • Christophe Nicolet
  • Silvio Giacomini
  • François Avellan
Part of the Springer Hydrogeology book series (SPRINGERHYDRO)


Numerical simulation and stability analysis of an islanded power network comprising 40 MW of hydropower, 20 MW of wind power, and 60 MW of gas-fired power plants are investigated. First, the modeling of each power plant is fully described. The wind farm is modeled through an aggregated model approach of 10 wind turbines of 2 MW and comprises a stochastic model of wind evolution with wind gust. The hydraulic power plant comprises the upstream reservoir, a 1,000 m gallery, a surge tank, the 500 m-long penstock feeding a low-specific-speed pump turbine and connected to the downstream tank through a 70 m-long tailrace water tunnel. The model of gas-fired power plant includes an upstream rotating compressor coupled to a downstream turbine and a combustion chamber in-between. To predict the performance of the gas turbine engine, both at design and off-design conditions, performance maps are integrated in the modeling. Then, the capability of the hydraulic power plant to compensate wind power variations or load rejections is investigated using the EPFL simulation software SIMSEN to perform time domain simulation of the entire mixed islanded power network. This study shows the evolution of the response time of the hydraulic part as function of the penstock length and highlights the influence of the hydraulic layout on the power system stability. The dynamic performances of such hydraulic power plants are of highest interest for improving stability of mixed islanded power network, but require reliable simulation model of the entire network for safety and optimization purposes.


Stability analysis Pump turbine Modeling Power network Simulation 



Cross-sectional area [m2]


Wave speed [m/s]


Hydraulic capacitance [m2]


Wind velocity [m/s]


Diameter [m]


Gravity [m/s2]


Frequency [Hz]


Head [m]


Hydraulic inductance [s2/m2]


Rotational speed [1/min]


Discharge [m3/s]


Hydraulic resistance [s/m2]


Reynolds number [-]


Viscoelastic resistance [s/m2]


Guide vanes opening [-]


Torque [Nm]


Local loss coefficient [-]


Dynamic viscosity [Pa s]


Expansion viscosity [Pa s]


Specific speed [-]


Density [kg/m3]



The authors would like to thank Swisselectric Research and the Energy Program of The Ark and the Foundation for Innovation of Valais Canton, for their financial support.


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Copyright information

© Springer Science+Business Media Singapore 2014

Authors and Affiliations

  • Christian Landry
    • 1
    Email author
  • Christophe Nicolet
    • 2
  • Silvio Giacomini
    • 1
  • François Avellan
    • 1
  1. 1.EPFL, Laboratory for Hydraulic MachinesLausanneSwitzerland
  2. 2.Power Vision engineering sàrlEcublensSwitzerland

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