Power Capability in Low Voltage DC Distribution Systems

• Main Authors: C.O. Gecan, M. Chindris, R. Bindiu
• Format: Article
• Language: English
• Published: Editura Universităţii "Petru Maior" 2009-12-01
• Series: Scientific Bulletin of the ''Petru Maior" University of Tîrgu Mureș
• Subjects: cables; line reconfiguration; DC systems; power capability; transmission distance
• Online Access: http://scientificbulletin.upm.ro/papers/2009/10/Power-Capability-in-Low-Voltage-DC-Distribution-Systems.pdf

Recent developments in power electronics components enable the use of power electronics in Low Voltage (LV) networks. This development makes the model of a Low Voltage Direct Current (LVDC) distribution system possible. The technical and economical benefits of this technology make possible the alternative hypothesis of using DC instead of AC distribution systems. Some aspects, such as increasing the capability of the existing lines, interconnecting distributed generation units and even supplying in DC some loads are creating additional requirements of using a LVDC distribution system. The paper presents some general considerations regarding cables used in a LVAC distribution system and different line reconfigurations witch enable the use of cobles in a LVDC distribution system. The reconfigurations are presented in respect of the DC network topologies: unipolar and bipolar. The central aim of this paper is to investigate capability of power transmission and to calculate the transmission distance for cables used in Low Voltage AC and DC distribution systems. Capability computation is considered in respect of two constrains imposed in the cables cross section selection: cable thermal limit and the maximum allowable voltage drop. Cable thermal limit is represented in calculations by the maximum rated current. The equations used to calculate the power capability are presented for single-phase and threephase AC networks and unipolar and bipolar DC networks. Based on these equations, comparisons between power capability of cables with different cross sections used in Low Voltage DC and AC distribution systems are realized and presented.