| Abstract: |
| When a fault occurs in a DC system, the fault current rises rapidly with no zero-crossing point which makes fault-line
selection and fault-type identification difficult. In this paper, an online detection and protection method based on
graph theory, namely the “double D method”, is proposed for fault-line selection and fault-type identification in DC
systems. In the proposed method, the entire distribution network is visualized as a “map” with vertices representing
the line convergence points and edges representing the connection lines. A network topology matrix “D” is formed
by detecting the current directions as the current directions are altered following a fault, whereas the current directions
at the ends of non-fault lines remain the same. In order to prevent misjudgment problems arising from power flow
reversal, the rates of change of the fault currents are used to further determine whether a fault has occurred and the
“double D method” is introduced to identify the fault type. Simulations results with different fault types verify the
effectiveness and reliability of the proposed method. |
| Key words: Network topology matrix, Double D method, Fault-line selection, Fault-type identification, Graph theory |
| DOI：10.1186/s41601-018-0098-9 |
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| Fund: |
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