A Protection Scheme of Ac Side Faults of Dc Distribution System

2014 ◽  
Vol 666 ◽  
pp. 107-111
Author(s):  
Yi Bo Gao ◽  
Jia Si Zeng ◽  
Peng Qiu ◽  
Yi Lu ◽  
Xiao Ming Huang ◽  
...  

Dc distribution systems are multiterminal systems characterized by complexity and mixed operation of ac and dc. Ac side faults are more likely to happen and may cause more serious consequences compared with dc transmission systems, thus must be considered seriously. In this paper, ac side faults of the prototype dc distribution system under high impedance grounding scheme are analyzed in detail. Fault characteristics of dc side voltages and currents under ac side faults are drawn and sorted. A protection scheme of ac side faults is proposed based on dc voltage and current measurements. The effectiveness of the protection scheme proposed is demonstrated by simulation under PSCAD/EMTDC.


Symmetry ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 775
Author(s):  
Sheng-Yu Tseng ◽  
Jun-Hao Fan

Due to the advantages of power supply systems using the DC distribution method, such as a conversion efficiency increase of about 5–10%, a cost reduction of about 15–20%, etc., AC power distribution systems will be replaced by DC power distribution systems in the future. This paper adopts different converters to generate DC distribution system: DC/DC converter with PV arrays, power factor correction with utility line and full-bridge converter with multiple input sources. With this approach, the proposed full-bridge converter with soft-switching features for generating a desired voltage level in order to transfer energy to the proposed DC distribution system. In addition, the proposed soft-switching full-bridge converter is used to generate the DC voltage and is applied to balance power between the PV arrays and the utility line. Due to soft-switching features, the proposed full-bridge converter can be operated with zero-voltage switching (ZVS) at the turn-on transition to increase conversion efficiency. Finally, a prototype of the proposed full-bridge converter under an input voltage of DC 48 V, an output voltage of 24 V, a maximum output current of 21 A and a maximum output power of 500 W was implemented to prove its feasibility. From experimental results, it can be found that its maximum conversion efficiency is 92% under 50% of full-load conditions. It was shown to be suitable for DC distribution applications.



Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 338
Author(s):  
Leslie Tracy ◽  
Praveen Kumar Sekhar

In this study, a low voltage solid-state circuit breaker (SSCB) was implemented for a DC distribution system using commercially available components. The design process of the high-side static switch was enabled through a voltage bias. Detailed functional testing of the current sensor, high-side switch, thermal ratings, analog to digital conversion (ADC) techniques, and response times of the SSCB was evaluated. The designed SSCB was capable of low-end lighting protection applications and tested at 50 V. A 15 A continuous current rating was obtained, and the minimum response time of the SSCB was nearly 290 times faster than that of conventional AC protection methods. The SSCB was implemented to fill the gap where traditional AC protection schemes have failed. DC distribution systems are capable of extreme faults that can destroy sensitive power electronic equipment. However, continued research and development of the SSCB is helping to revolutionize the power industry and change the current power distribution methods to better utilize clean renewable energy systems.



2019 ◽  
Vol 9 (3) ◽  
pp. 582 ◽  
Author(s):  
Hasan Gelani ◽  
Faizan Dastgeer ◽  
Kiran Siraj ◽  
Mashood Nasir ◽  
Kamran Niazi ◽  
...  

The paper investigates the system efficiency for power distribution in residential localities considering daily load variations. Relevant system modeling is presented. A mathematical model is devised, which is based on the data from the Energy Information Administration (EIA), USA, for analysis. The results reveal that the DC distribution system can present an equivalent or even better efficiency compared to the AC distribution network with an efficiency advantage of 2.3%, averaged over a day. Furthermore, the distribution systems are compared under various capacities of solar PV accounting for the effect of variation in solar irradiation over time.



2021 ◽  
Vol 9 ◽  
Author(s):  
Wei Teng ◽  
Yuejiao Wang ◽  
Shumin Sun ◽  
Yan Cheng ◽  
Peng Yu ◽  
...  

DC power distribution systems will play an important role in the future urban power distribution system, while the charging and discharging requirements of electric vehicles have a great impact on the voltage stability of the DC power distribution systems. A robust control method based on H∞ loop shaping method is proposed to suppress the effect of uncertain integration on voltage stability of DC distribution system. The results of frequency domain analysis and time domain simulation show that the proposed robust controller can effectively suppress the DC bus voltage oscillation caused by the uncertain integration of electric vehicle, and the robustness is strong.





2010 ◽  
Vol 61 (4) ◽  
pp. 193-204 ◽  
Author(s):  
Reza Noroozian ◽  
Mehrdad Abedi ◽  
Gevorg Gharehpetian

Combined Operation of AC and DC Distribution System with Distributed Generation Units This paper presents a DC distribution system which has been supplied by external AC systems as well as local DG units in order to demonstrate an overall solution to power quality issue. In this paper, the proposed operation method is demonstrated by simulation of power transfer between external AC systems, DG units, AC and DC loads. The power flow control in DC distribution system has been achieved by network converters and DG converters. Also, the mathematical model of the network, DG and load converters are obtained by using the average technique, which allows converter systems accurately simulated and control strategies for this converters is achieved. A suitable control strategy for network converters has been proposed that involves DC voltage droop regulator and novel instantaneous power regulation scheme. Also, a novel control technique has been proposed for DG converters. In this paper, a novel control system based on stationary and synchronously rotating reference frame has been proposed for load converters for supplying AC loads connected to the DC bus by balanced voltages. The several case studies have been studied based on proposed methods. The simulation results show that DC distribution systems including DG units can improve the power quality at the point of common coupling (PCC) in the power distribution system or industrial power system.



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