GunnsElectShort - nasa/gunns GitHub Wiki

This link extends GunnsBasicConductor with an electrical short-circuit model. The short-circuit is modeled as a user-controlled conductance between the two connected nodes. There are several malfunction modes to control the conductance, listed below. Multiple of these malfunction modes can be activated by the user at the same time, but only one takes effect at a time. These are listed in the order of precedence, with the highest priority mode listed last:

• Constant Resistance: the short is modeled as a constant resistance.
• Initial Current: the short is a constant resistance calculated to create the desired initial current based on network conditions at the moment of activation. After starting, the actual current will vary as the network changes.
• Initial Power: similar to Initial Current, except based on an initial desired power value.
• Constant Current: the short is a constant-current load.
• Constant Power: the short is a constant-power load.

Note that the Constant Current and Constant Power modes do not have a low-voltage cutoff, so they can cause unwanted network convergence failures if large enough. Care should be taken when using these modes.

(Note this link is not available in the obsolete GunnShow tool.)

This link can be connected between any two nodes, similar to GunnsBasicConductor. It can also be moved in run-time via the Link Dynamic Node Mapping.

These are limitations on the port connections to nodes that the link enforces in run-time:

• Same as GunnsBasicConductor

These are extra rules you should always try to follow:

• You may be tempted to add a short link on every node in your power system model, but this may lead to a lot of clutter in your network drawing. As an alternative, consider using a smaller set of links and having the user move them, via the Link Dynamic Node Mapping, to where the short circuits are desired during run-time.

This link has no configuration data.

• malfBlockageFlag (default = false): Initial active (true) or inactive (false) state of the blockage malfunction. Note that this blockage malfunction should not be used in combination with the Constant Current or Constant Power malfunctions.
• malfBlockageValue (default = 0.0, must be (0-1)): Initial value of the blockage malfunction. This value is an additional scalar on the conductance resulting from the short malfunctions. For instance if the Constant Resistance malfunction is used to control the conductance to 10 (1/ohm), then activating this blockage malfunction with a value of 0.5 would result in a final conductance of 5 (1/ohm).
• malfMinimumVoltage (default = 0.0 (V)): This is a placeholder term for a future upgrade. It currently has no function.
• malfConstantPowerFlag (default = false): Initial active (true) or inactive (false) state of the constant power malfunction. Note that this should not be used in combination with the blockage malfunction.
• malfConstantPowerValue (default = 0.0 (W)): Initial constant power value of the malfunction. Positive or negative values can be entered, but the link will just take the absolute value — this malfunction can only dissipate power through the link and a negative value can’t be used to create power.
• malfConstantCurrentFlag (default = false): Initial active (true) or inactive (false) state of the constant current malfunction. Note that this should not be used in combination with the blockage malfunction.
• malfConstantCurrentValue (default = 0.0 (amp)): Initial constant current value of the malfunction. Positive or negative values can be entered, but the link will just take the absolute value — this malfunction can only dissipate power through the link and a negative value can’t be used to create power.
• malfInitialPowerFlag (default = false): Initial active (true) or inactive (false) state of the initial power malfunction.
• malfInitialPowerValue (default = 0.0 (W)): Initial power value of the malfunction. Positive or negative values can be entered, but the link will just take the absolute value — this malfunction can only dissipate power through the link and a negative value can’t be used to create power.
• malfInitialCurrentFlag (default = false): Initial active (true) or inactive (false) state of the initial current malfunction.
• malfInitialCurrentValue (default = 0.0 (amp)): Initial current value of the malfunction. Positive or negative values can be entered, but the link will just take the absolute value — this malfunction can only dissipate power through the link and a negative value can’t be used to create power.
• malfResistanceFlag (default = false): Initial active (true) or inactive (false) state of the constant resistance malfunction.
• malfResistanceValue (default = 0.0 (ohm)): Initial constant resistance value of the malfunction. Positive or negative values can be entered, but the link will lower-limit the value to DBL_EPSILON to avoid zero or negative resistances.

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