Journal of Electrical Engineering and Technology

The Korean Institute of Electrical Engineers (대한전기학회)
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Quick and Accurate Computation of Voltage Stability Margin

  • Karbalaei, Farid (Faculty of Electrical Engineering, Shahid Rajaee Teacher Training University (SRTTU)) ;
  • Abasi, Shahriar (Electrical Engineering Department, Faculty of Engineering, Razi University)
  • Received : 2015.03.01
  • Accepted : 2015.08.06
  • Published : 2016.01.01
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Abstract

It is well known that the behavior of PV curves is similar to a quadratic function. This is used in some papers to approximate PV curves and calculate the maximum-loading point by minimum number of power flow runs. This paper also based on quadratic approximation of the PV curves is aimed at completing previous works so that the computational efforts are reduced and the accuracy is maintained. To do this, an iterative method based on a quadratic function with two constant coefficients, instead of the three ones, is used. This simplifies the calculation of the quadratic function. In each iteration, to prevent the calculations from diverging, the equations are solved on the assumption that voltage magnitude at a selected load bus is known and the loading factor is unknown instead. The voltage magnitude except in the first iteration is selected equal to the one at the nose point of the latest approximated PV curve. A method is presented to put the mentioned voltage in the first iteration as close as possible to the collapse point voltage. This reduces the number of iterations needed to determine the maximum-loading point. This method is tested on four IEEE test systems.

Keywords

References

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