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Jonathan edited this page Aug 17, 2020 · 4 revisions

Cable

The Cable is a cable model that does not include cable sizing logic. It assumes a known resistance and inductance are specified and only includes performance calculations.

Usage

  • The input design parameters that must be specified by the modeler when creating an instance of this Cable component are cable resistance and inductance (R and L), and mass specific ampacity (SpecificAmperage). In other words, the cable impedance must be known to use this component.

  • This component supports DC and AC (single or multiphase) power. At instantiation, this component's power type is unspecified. NPSS Power System Components need to have a power type in order to correctly run power calculations. For this component, the power type is typically set by calling the findSourcesAndPropagate() method at the top level assembly (see ElectricPort).

  • This component does not contain a node, and so starts each iteration with its port voltages unknown. The NPSS Power System Library requires that all components that contain nodes all have a prePass() method specified that pushes node voltage information, via their ports to all components that do not contain nodes and so do not know their voltages. The intent is that after all component prePass() methods are automatically called, all components in the system will then have port voltages specified. Then during the normal iteration, components that don't contain nodes such as this one, will execute first. These components typically transmit power from one node to another and do not transform it from one kind to another (e.g. cables and breaker). These execute first in the solver sequence, and inside their calculate() methods, they calculate their currents, which are then passed via the ports, to all other components in the circuit. So after these nodeless transmission components execute, all electric port voltages and currents should be specified, and so all other components are free to run.

  • This component, like other power system components in the NPSS Power System Library, can optionally include thermal models. An optional thermal model is enabled by setting switchThermPort to TRUE, and plugging an EThermalMass subelement into the S_eThermMass socket. Doing these will add a temperature state (existing within EThermalMass) and a thermal port to the model. The thermal port is intended to connect this component to a second component that represents the mechanism by which heat is extracted from this component. This second component could represent a heat exchanger, cold plate, or just model heat transfer from the first component to the surrounding environment. For more information see EThermalMass.

  • Solver independents and dependents are not used in the Cable component, and there is no sizing logic included in this component, other than the mass calculations described above.

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