NEPLAN | Voltage Stability

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This module is an ideal tool to provide insight into the nature of voltage stability problems. It allows the examination of a wide range of system conditions  providing four approaches for static voltage stability analysis of power systems:  V-Q curves, P-V curves, V-Q sensitivity analysis and Q-V eigenvalue analysis (modal analysis).

General Characteristics

  • Automatic calculation of P-V curves, V-Q curves, dV/dQ self-sensitivities, dV/dQ mutual sensitivities, eigenvalues, eigenvectors, bus participation factors, branch participation factors and generator participation factors.
  • Result tables: results are presented in clear form and can be exported by Copy-Paste-methods to external programs (e.g. MS-Excel).
  • Graphical results: results can be visualized by the fully integrated graphical results manager.
  • Export files: results are stored in text files for advanced data export.
  • Charts can be easily printed and exported to external programs (e.g. MS-Word) by clipboard functions. A variety of chart options is available.
  • Input: standard load flow input data


  • Identification of weak / not controllable / unstable areas
  • Identification of weak and heavily loaded links
  • Proper distribution of reactive reserves in order to maintain an adequate voltage stability margin
  • Voltage sensitivity information
  • Degree of voltage stability
  • Most effective measures in improving voltage stability