| Title |
Robust algorithm for estimating voltage stability by the modified method of sensitivity index dP/de of real value on voltage vector |
| Keywords |
Voltage Stability ; D P_{k} / d {ek} =0 ; Hessian Matrix ; P - V Curve |
| Abstract |
Recently, much attention has been paid to problems which is concerned with voltage instability phenomena and much works on these phenomena have been made. In this paper, by substituting d P_{k} d e_{k} ( v^{ rarw}= e +j f) for P_{k} in conventional load flow, direct method for finging the limit of voltage stability is proposed. Here, by using the fact that taylor se- ries expansion in .DELTA. P_{k} and .DELTA. Q_{k} is terminated at the second-order terms, constraint equation (d P_{k} d e_{k} =0) and power flow equations are formulated with new variables .DSLTA. e and .DELTA.f, so partial differentiations for constraint equation are precisely calculated. The fact that iteratively calculated equations are reformulated with new variables .DELTA.e and .DELTA.f means that limit of voltage stability can be traced precisely through recalculation of jacobian matrix at e+.DELTA.e and f+.DELTA.f state. Then, during iterative process divergence may be avoid. Also, as elements of Hessian mat rix are constant, its computations are required only once during iterative process. Results of application of the proposed method to sample systems are presented. (author). 13 refs., 11 figs., 4 tab. |