Power Quality Improvement Using a New Structure of Fault Current Limiter
Seyed Hossein Hosseini1, M. Tarafdar Hagh2, M. Jafari2, S. B. Naderi2, S. Gassemzadeh1 1 Islamic Azad University, Science and research branch of East Azerbaijan
Faculty of Electric & Electronic Engineering, University of Tabriz, Tabriz, IRAN (Tel/Fax: +98-411-3300819; Email: email@example.com) II. VOLTAGE SAG STUDY IN RADIAL POWER SYSTEM Fig. 1 shows a simplified radial power system. Feeder F1 supplies a sensitive load. With a fault in feeder F2, Point of Common Coupling (PCC) voltage reduces sharply. In case of three phase fault at the beginning of line, PCC voltage becomes almost zero and sensitive load supplying interrupts. Positive sequence equivalent circuit of such system is shown in Fig. 2. To calculate the voltage sag, simple voltage divider method is introduced in . PCC voltage can be expressed by (1):
Abstract-In this paper, power quality improvement by using a new structure of non superconducting fault current limiter (NSFCL) is discussed. This structure prevents voltage sags on Point of Common Coupling (PCC) just after fault occurrence, because of its fast operation. On the other hand, previously used structures produce harmonics on load voltage and have ac losses in normal operation. New structure has solved this problem by using dc voltage source. The proposed structure is simulated using PSCAD/EMTDC software and simulation results are presented to validate the effectiveness of this structure.
Electric power quality can be defined as the capacity of an electric power system to supply energy for a load in acceptable ZK VPCC = VS (1) quality. Consequently, power quality problems have became a Z K + (Z S + Z t ) major concern in the power systems [1, 2]. Voltage sag is a rather old power quality problem that Where: nowadays becomes important because of sensitive loads Z t : Transformer impedance growth . Worldwide experience demonstrates...