Abstract
Background: With the increasing development of voltage source converter based high
voltage direct current (HVDC), it will become a reality to interconnect different DC networks into
DC grid with DC-DC converters.
Methods: In this paper, three operation scenarios for the DC grid with DC-DC converters are proposed,
by which the DC networks can reinforce each other with relative independence. In order to
achieve the flexible switching of the proposed scenarios, the DC-DC combined control and principle
of parameter selection are presented. In addition, two coordination controls for different scenarios are
given to optimize the distribution of unbalanced power when the disturbances occur in the grid. With
the proposed scenarios and control strategy, the impacts caused by the disturbances are alleviated and
the uninterrupted operation of the grid is guaranteed.
Results: A simulation model is established on the PSCAD/EMTDC and the simulation results verify
the effectiveness of the proposed operation scenarios and control strategy.
Conclusion: Finally, the effectiveness of the proposed operation scenarios and control strategy is verified
by the simulation results in PSCAD/EMTDC.
Keywords:
DC grid, voltage source converter based high voltage direct current (VSC-HVDC), DC-DC converter, operation
scenario, coordination control, renewable energy resource.
Graphical Abstract
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