A New Estimate Method of a Soft-Fault Parameter Value in Self-Healing Circuits Part I: Principles
Zhihua Li, Tingyu Jiang, Li Liuchang · 2016
This study proposes an estimate method of the element's soft-fault parameter value (SFPV) based on steady-state node-voltage when a soft-fault of occurs. The method defines a radial direction deviation angle (RDDA), two element position coefficients (EPCs), and a parameter deviation coefficient (PDC) for a soft-fault element, and then utilizes the impedance circle to set up an equation among a RDDA, two unknown EPCs, and a PDC of the element. The method artificially simulates two soft-faults to get the two RDDAs and two PDCs of the element through a conformal transformation between the SSNVV circle and the impedance circle, and then solves two unknown EPCs via the previous built equation. When a new soft-fault of the element occurs, the method measures new faulty SSNVV to calculate new RDDA, and uses the new RDDA and previous computed EPCs to solve the PDC of new SFPV via the previous built equation. Finally, the SFPV corresponding to the PDC can be computed. This part of the paper provides the principles of the proposed method. Two examples and a programming strategy are described in the second part of the paper.