Determination of Flicker Transfer Coefficients Near Large Synchronous Generators

Large disturbing loads such as electric arc furnaces (EAF) create fluctuations in source voltage at the point of common coupling (PCC). These voltage fluctuations then propagate throughout the power system with varying degrees of attenuation. The amount of attenuation is, in general, a function of system impedance and load composition, and can be characterized by what is known as a flicker transfer coefficient. The frequency response of synchronous generators near 60 Hz has a significant effect on flicker propagation, particularly in networked HV or EHV systems. To date, information available in the literature has not adequately described this phenomenon from a theoretical perspective or shown how to take this affect into consideration when computing flicker transfer coefficients. The following paper addresses these issues by: 1) providing a formal description of a synchronous generator model that can be used to determine flicker transfer coefficients when traditional modeling methods may not be appropriate and 2) providing a novel way of calculating flicker transfer coefficients using the described machine model. Synchronized flicker measurements, made at an EAF installation and nearby generating facility in the Southern Company service area, were used to validate the results of the proposed method.