Tips on Creating DC Systems

The following are recommendations when creating DC one-lines.

  • Always use an inverter or a rectifier to interconnect AC and DC systems.
  • Choose the appropriate voltage for AC or DC buses. For rectifiers and inverters without voltage control, the typical ratio is:
  • VDC = 1.35 * VAC

    AC voltage is rms value whereas the DC is average. Failure to set voltages correctly could result in an incorrect power flow solution.

  • AC equipment cannot be connected to DC equipment.
  • While placing breakers on inverters or rectifiers, connect the AC breaker on the AC side and DC breaker on the DC side.
  • Make sure breakers and fuses are "in-line" with the branch equipment. If the breaker is "in-line" with the equipment, then moving the breaker left or right on the one-line will move the equipment as well. See below.
  • DC switches are currently not available in the equipment palette. For a DC switch, use a DC breaker instead.

Figure 1: Breakers Shown In and Out of Line

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