Hasen, Suud; Aydın, Ömer; Ayasun, Saffet; Sönmez, Şahin

This article examines the effect of virtual inertia and damping (VID) control on the stability regions of time-delayed load frequency control (LFC) systems. Because of the substantial integration of renewable energy sources (RES) and the utilization of an open communication network for sending/receiving data and control signals, the system inertia significantly decreases, and inevitable delays are observed, both of which adversely affect the controller performance and frequency stability. For improving the stability of LFC systems including RES and delays, this study proposes the integration of the VID control and determines stability regions using the method of stability boundary locus. The regions’ boundaries are substantiated by time-domain simulations and a quasi-polynomial mapping-based root finder (QPmR) algorithm. A wide-ranging evaluation of the VID coefficients’ effects on the stability region and the system’s frequency response are presented. Results evidently divulge that with the integration of the VID control, stability regions get larger, the frequency dynamic is improved, and unstable LFC systems with delays are stabilized.

Uzunoğlu, Cengiz Polat; Babacan, Yunus; Kaçar, Fırat; Ug˘ur, Mukden

A gas discharge lamp is a device, which operates as a light source by producing electrical discharge in ionized gaseous medium. Discharge lamps are commonly used in the market and according to their physical properties they can be mainly classified in three different categories: high pressure, low pressure and high-intensity lamps. Ionized gases have tendency to produce ongoing discharges and finally electrical arcs, which exhibit memristor characteristics proposed by Leon Chua. This paper introduces a novel fully floating memristor circuit emulator with tunable threshold characteristics which mimic discharge lamp characteristics. In order to investigate discharge lamp characteristics a test set-up is designed and commercially available discharge lamps are tested. The proposed memristor circuit displays distinctive characteristics in contrast to well-known smooth switching memristor characteristics in terms of hard switching capability. Proposed memristor has unique switching behavior and fully capable of modeling discharge lamps since it satisfies required zero-crossing, pinched hysteresis and frequency dependent characteristics of the discharge lamps. The comparisons of the current-voltage characteristics for both memristor and discharge lamps are supplied and investigated.