Fuzzy-logic method for adjustment of variable parameters in load-flow calculation

Abstract

The paper presents a new approach using fuzzy logic to adjust variable parameters so as to meet constraints during load-flow study. Parameters to be adjusted include transmission-line impedance, phase angle and transformer tap position, and the constraints are transmission-line power flow and bus-voltage magnitude. Versatile apparatus which are used to tune these parameters include the thyristor-controlled series compensator, thyristor-controlled phase shifter, unified power-flow controller and on-load tap changer. The proposed approach is particularly aimed at assisting convergence in load flow programs. The parameters to be adjusted are decoupled from the main body of the load-flow formulation. The methodology for parameter adjustment is conducted by using fuzzy logic.