scholarly journals A Protection Method for DC Distribution Network with Single Pole Grounding Based on Integrative Two-terminal MMC

2021 ◽  
Vol 2066 (1) ◽  
pp. 012104
Author(s):  
Hua Jiang ◽  
Xinglai Shen ◽  
Bing Ma
Keyword(s):  
Distribution Network ◽  
Fault Line ◽  
Analysis Model ◽  
Transient Currents ◽  
Similarity Principle ◽  
Dc Distribution ◽  
Protection Method ◽  
Security And Reliability ◽  
Simulation Results ◽  
Tie Line

Abstract Based on the analysis model of unipolar grounding fault occurred in two-terminal MMC DC distribution network, the characteristics of unipolar grounding fault are studied. The similarity characteristics of transient currents between the fault line and the non-fault line are analyzed when the fault is located in the feeder, tie line and bus respectively. According to the characteristics of single-pole grounding fault and the similarity principle, a new single-pole grounding protection method for DC distribution network based on two-terminal MMC is proposed. The simulation results show that the proposed single-pole grounding protection method can accurately determine the single-pole grounding fault at any position of the DC distribution network. The research results can effectively solve the problem of single-pole grounding protection in DC distribution network, and effectively improve the security and reliability of DC distribution network.

scholarly journals A Method of Single-terminal MMC Single-pole Grounding Protection for DC Distribution Network Based on Multi-class Similarity Analysis

2021 ◽  
Vol 2066 (1) ◽  
pp. 012105
Author(s):  
Wei Zhang ◽  
YaFei Cao ◽  
YuanChun Fan
Keyword(s):  
Distribution Network ◽  
Simple Calculation ◽  
Similarity Analysis ◽  
Fault Current ◽  
Analysis Model ◽  
Ground Fault ◽  
Dc Distribution ◽  
Negative Current ◽  
Safety And Reliability ◽  
Simulation Results

Abstract Based on the analysis model of single-pole to ground fault occurred in single-ended MMC DC distribution network, the characteristics of single-pole to ground fault are studied. The similarity of positive and negative current between the fault feeder and the non-fault feeder, the similarity of fault current between the fault feeder and the non-fault feeder, and the similarity of positive and negative current sum between the two feeders are analyzed. Based on the differences among the three types of similarity, a new method of single-pole grounding protection for DC distribution network with MMC based on multi-type similarity analysis is proposed. The simulation results show that this method can accurately determine the fault feeder, and has the characteristics of strong anti-interference ability, simple calculation and easy implementation. It can effectively solve the problem of single-pole grounding protection of DC distribution network and effectively improve the safety and reliability of power supply of DC distribution network.

scholarly journals A Fault Line Selection Method for DC Distribution Network Using Multiple Observers

Energies ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1245 ◽  
Author(s):  
Xipeng Zhang ◽  
Nengling Tai ◽  
Pan Wu ◽  
Xiaodong Zheng ◽  
Wentao Huang
Keyword(s):  
Distribution Network ◽  
Initial Result ◽  
Fault Current ◽  
Fault Line ◽  
Fault Line Selection ◽  
Dc Distribution ◽  
Line Selection ◽  
Selection For ◽  
Line Network ◽  
Peak Value

This paper proposes a method of fault line selection for a DC distribution network. Firstly, the 1-mode current is calculated using the measured currents of the positive and the negative line. Then, it is time reversed and further decomposed by wavelet technology. Secondly, the lossless mirror line network is established according to the parameters and the topology of the DC distribution network. Thirdly, it is presumed that several virtual current sources are employed at the locations where the corresponding observers are, and the values of these current sources are equal to the processed 1-mode currents. Fourthly, a fault is placed at every point of the lossless mirror line network the RMS value of every assumed fault current is calculated. During this process, the phase coefficient of every lossless mirror line is set to vary along with the length of the line obeying Gaussian distribution. Finally, the line with the peak value of the RMS values of the currents is selected as the fault line. The result of fault line selection is updated using the fewest observers that are set in advance according to the initial result. A DC distribution network is simulated in PSCAD/EMDTC to verify the correctness of the proposed method.

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