Protection Principle for a DC Distribution System with a Resistive Superconductive Fault Current Limiter

Abstract

A DC distribution system, which is suitable for access to distributed power generation and DC loads, is one of the development directions in power systems. Furthermore, it could greatly improve the energy efficiency and reduce the loss of power transportation. The huge short circuit current is always a great threat to the safety of the components, especially the capacitors and diodes. A resistive superconductive fault current limiter (SFCL), which could respond quickly once a fault happens and limit the fault current to a relatively low level, becomes a good solution to this problem. In this paper, the operational principle of the resistive SFCL is introduced first, and then, the DC short-circuit fault characteristic of the DC distribution system with the SFCL is analyzed and the effectiveness of the SFCL verified. In order to realize the selectivity of the protection in the DC distribution system with SFCL, a new transient current protection principle based on Ip (the peak value of the current) and tp (the transient time that the current takes to reach its peak value) is proposed. Finally, a model of a 10-kV DC distribution system with an SFCL is established and simulated in PSCAD/METDC. Simulation results have demonstrated the validity of the analysis and protection principle.

Technical Evaluation of Superconducting Fault Current Limiters Used in a Micro-Grid by Considering the Fault Characteristics of Distributed Generation, Energy Storage and Power Loads

“…Since the SFCL parameters are respectively set as L 1 = 50 mH and R sc = 10 Ω, L 1 = 70 mH and R sc = 30 Ω, L 1 = 90 mH and R sc = 50 Ω, the fault current's peak value can be respectively suppressed to 180 A, 117 A, 89 A, and the current-limiting ratio is about 75.7%, 84.2%, 88%. Figures [16][17][18][19] show the DG voltage, exchange power and frequency fluctuations of the micro-grid system under the internal fault. From these figures, the positive effects of the two SFCLs can be observed.…”

“…Since the power Load 1 is shorted, the decrease of the exchange power and the full utilization of the local DG units can help to achieve the power balance. In addition, taking the enhancement of the micro-grid's frequency stability as an example, employing the SFCLs can make Figures [16][17][18][19] show the DG voltage, exchange power and frequency fluctuations of the micro-grid system under the internal fault. From these figures, the positive effects of the two SFCLs can be observed.…”

“…There are many remarkable merits, including: sub-cycle operation in response to faults; reduced damage at the point of fault; and critical protection of relevant power equipment [14][15][16][17][18][19]. Currently, some basic research works have been done to promote the application of one or more SFCLs in a micro-grid.…”

A Novel Protection and Location Scheme for Pole-to-Pole Fault in MMC-MVDC Distribution Grid

“…With the development of modern power electronics technology and the increase of new energy power generation systems, the Medium Voltage Direct Current (MVDC) distribution grid will have a good prospect [1][2][3][4]. A Modular Multilevel Converter (MMC) usually has a large number of sub-modules [5].…”

Performance Investigation and Optimization of a Novel Hybrid Saturated-Core Fault-Current Limiter Considering the Leakage Effect

“…Fault-current limiter devices (FCL) are becoming a promising technology to limit fault current. There are several types of FCLs [6][7][8]. The saturated-core fault-current limiter (SCFCL) has attracted worldwide attention from researchers and companies and has the advantages of fault self-detection, fast action and a high withstanding voltage [9][10][11].…”