scholarly journals Development and Validation of a Special Protection System for Internal Fault in a High-Power Three-Level NPC VSC

Energies ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5937
Author(s):  
Mattia Dan ◽  
Loris Zanotto ◽  
Elena Gaio ◽  
Carlo Panizza ◽  
Claudio Finotti ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
High Power ◽  
Short Circuit ◽  
Protection System ◽  
Stored Energy ◽  
Power Switching ◽  
Medium Voltage ◽  
Internal Fault ◽  
Conversion System ◽  
Development And Validation

This paper describes the development and validation of an innovative protection system based on medium-voltage fuses for a high-power switching conversion system. This special conversion system, rated to deliver about 56 MW to the load, is based on neutral-point clamped IGCT inverters, connected to the same dc link through a set of distributed busbars, with a dc-link voltage of 6.5 kV and a capacitive stored energy up to 837 kJ. The sudden release of this energy in case of a switch failure in one inverter and the subsequent short circuit of one leg can lead to destructive consequences. From the analysis of different protection strategies, performed by numerical simulations of the fault evolutions, the developed solution based on medium-voltage fuses was found the only provision able to cope with such high stored energy and uncommon circuit topology. Custom fuses were developed for this application, and a specially tailored test was designed for validating the fuse selection. The paper, after summarizing the work carried out to simulate the fault evolution and select the protection, presents the analyses carried out to set up the validation test, and describes and discusses the results of the test and the complementing numerical simulations, which demonstrated the effectiveness of the protection system.

Analysis and Optimization of Modulation Transitions in Medium Voltage High Power Converters

2021 ◽  
pp. 1-1
Author(s):  
Hector Fernandez-Rebolleda ◽  
Alain Sanchez-Ruiz ◽  
Salvador Ceballos ◽  
Angel Perez-Basante ◽  
Juan Jose Valera Garcia ◽  
...  
Keyword(s):  
High Power ◽  
Power Converters ◽  
Medium Voltage

scholarly journals Cell/Module Integration Technology with Wire-Embedded EVA Sheet

2021 ◽  
Vol 11 (9) ◽  
pp. 4170
Author(s):  
Jeong Eun Park ◽  
Won Seok Choi ◽  
Donggun Lim
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
High Power ◽  
Short Circuit ◽  
Optical Loss ◽  
Manufacturing Cost ◽  
Power Module ◽  
Manufacturing Method ◽  
Front Electrode ◽  
The Wire

Silicon wafers are crucial for determining the price of solar cell modules. To reduce the manufacturing cost of photovoltaic devices, the thicknesses of wafers are reduced. However, the conventional module manufacturing method using the tabbing process has a disadvantage in that the cell is damaged because of the high temperature and pressure of the soldering process, which is complicated, thus increasing the process cost. Consequently, when the wafer is thinned, the breakage rate increases during the module process, resulting in a lower yield; further, the module performance decreases owing to cracks and thermal stress. To solve this problem, a module manufacturing method is proposed in which cells and wires are bonded through the lamination process. This method minimizes the thermal damage and mechanical stress applied to solar cells during the tabbing process, thereby manufacturing high-power modules. When adopting this method, the front electrode should be customized because it requires busbarless solar cells different from the existing busbar solar cells. Accordingly, the front electrode was designed using various simulation programs such as Griddler 2.5 and MathCAD, and the effect of the diameter and number of wires in contact with the front finger line of the solar cell on the module characteristics was analyzed. Consequently, the efficiency of the module manufactured with 12 wires and a wire diameter of 0.36 mm exhibited the highest efficiency at 20.28%. This is because even if the optical loss increases with the diameter of the wire, the series resistance considerably decreases rather than the loss of the short-circuit current, thereby improving the fill factor. The characteristics of the wire-embedded ethylene vinyl acetate (EVA) sheet module were confirmed to be better than those of the five busbar tabbing modules manufactured by the tabbing process; further, a high-power module that sufficiently compensated for the disadvantages of the tabbing module was manufactured.

Research of Large-Scale Offshore Wind Farm Collection System Short Circuit Equivalent Network

2013 ◽  
Vol 448-453 ◽  
pp. 1732-1737
Author(s):  
Liu Bin ◽  
Hong Wei Cui ◽  
Li Xu ◽  
Kun Wang ◽  
Zhu Zhan ◽  
...  
Keyword(s):  
Large Scale ◽  
Wind Farm ◽  
Short Circuit ◽  
Short Circuit Current ◽  
System Optimization ◽  
Offshore Wind ◽  
Offshore Wind Farm ◽  
Collection System ◽  
Medium Voltage ◽  
The Impact

This paper analyses the characteristics of large-scale offshore wind farm collection network and the impact of the medium voltage collection system optimization,while from the electrical technology point,it proposes the short circuit current of the collection network computational model and algorithms,based on the principle of equivalent circuit.Taking a wind power coolection system planned for a certain offshore wind farm planning for example, the validity of the model and algorithm is verified.

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