Abstract
This paper presents a new concept for finding saddle-node bifurcation (SNB) points in voltage stability analysis of power systems by applying the extended functional method (EFM). This method enables the finding of the SNB point of power systems by directly calculating the extreme values of a nonsmooth variational functional, which is obtained in its turn by the so-called nonlinear generalized Collatz-Wilandt formula. The main theoretical result establishes the EFM applicability for finding the maximum loading capacity of power systems. The maximum loading capacity of the power system is shown to be located at the maximizing point of the nonsmooth function of bifurcations. The subgradient method for nonsmooth functions was applied. The EFM was performed on various IEEE test systems to find SNB points, and the results were compared with those obtained with the Continuation Power Flow (CPF) and the Point of Collapse (PoC) method. The simulation results show that the proposed method is robust and, unlike the PoC method, finds the SNB point even when good guessing of the turning point is not available. Tasks such as tracking an SNB point displaced by a contingency and infeasible power flow were performed successfully by using the EFM.
Highlights
Bifurcations are nonlinear phenomena related to a qualitative and abrupt change in nonlinear systems’ behavior as a consequence of the variation of one or more parameters
STUDY CASES we present the performance of the extended functional method (EFM) applied on various tasks and the comparison with Continuation Power Flow (CPF) and Point of Collapse (PoC) method
We presented a new concept for finding saddle-node bifurcation points based on the Extended Functional Method
Summary
Bifurcations are nonlinear phenomena related to a qualitative and abrupt change in nonlinear systems’ behavior as a consequence of the variation of one or more parameters. The continuation power flow methods (CPF) [18], [19] are indirect methods that are widely applied to determine the relationship between power demand and voltage profile (P-V curve) These methods compute the bifurcation point by increasing the load until the loadability limit or turning point is reached. In [29], for instance, the maximum loadability is computed via factored power flow, whereas [30], presents a fast method for finding LIBs. The contribution of this paper is the proposal of a conceptually new direct method for computing SNB points (turning points) for voltage stability assessment.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
