Buildings.Electrical.Interfaces

This package contains interfaces and partial models that are inherited by other components

Information

This package contains basic classes that are used to build component models for electrical systems. The classes are not directly usable, but can be extended when building a new model.

Extends from Modelica.Icons.InterfacesPackage (Icon for packages containing interfaces).

Package Content

Name	Description
BaseTerminal	Empty connector used by partial models
CapacitiveLoad	Partial model of a capacitive load
Ground	Generalized model of a ground connection.
Impedance	Partial model representing a generalized impedance
InductiveLoad	Partial model of an inductive load
Load	Partial model for a generic load
PartialBaseTwoPort	Model of a generic two port component
PartialConversion	Model representing a generic two port system for conversion
PartialPV	Base model for a PV system
PartialPVOriented	Base model of a PV system with orientation
PartialPvBase	Partial model with basic parameters for PVs
PartialTwoPort	Model of a generic two port component with phase systems
PartialWindTurbine	Partial model of a wind turbine with power output based on table as a function of wind speed
PartialWindTurbineBase	Base class for turbine model that contains basic parameters
ResistiveLoad	Partial model of a resistive load
Source	Partial model of a generic source.
Terminal	Generalized electric terminal
VariableVoltageSource	Partial model of a generic variable voltage source.
PartialAcDcParameters	Partial model that contains basic parameters for a DC/AC conversion system
PartialPluggableUnbalanced	Partial interface for unbalanced loads

Buildings.Electrical.Interfaces.BaseTerminal

Empty connector used by partial models

Information

Modelica definition

Buildings.Electrical.Interfaces.CapacitiveLoad

Partial model of a capacitive load

Information

This is a model of a generic capacitive load. This model is an extension of the base load model Buildings.Electrical.Interfaces.PartialLoad.

This model assumes a fixed power factor pf when the flag use_pf_in = false otherwise it uses the power factor specified by the input pf_in.

The power factor (either the input or the parameter) is used to compute the reactive power Q given the active power P

Q = - P * tan(arccos(pf))

Extends from Load (Partial model for a generic load).

Parameters

Connectors

Modelica definition

Buildings.Electrical.Interfaces.Ground

Generalized model of a ground connection.

Information

Given a generic electric connector Buildings.Electrical.Interfaces.Terminal this model imposes the following condition on the voltage V[PhaseSystem.n]

V = 0,

where 0 is a null vector of length PhaseSystem.n.

Parameters

Connectors

Modelica definition

Buildings.Electrical.Interfaces.Impedance

Partial model representing a generalized impedance

Information

This model represents a generalized interface for an impedance.

The model has a single generalized electric terminal of type Buildings.Electrical.Interfaces.Terminal that can be redeclared. The impedance can be of different types:

1. resistive,
2. inductive,
3. resistive and inductive,
4. capacitive, and
5. resistive and capacitive.

The values of the resistance R, capacitance C and inductance L can be specified as parameters of the model.

The values of the resistance R, capacitance C and inductance L can also be specified by using the input variables y_R, y_C, and y_L that are Real values between [0,1].
These input values are enabled by the boolean flags use_R_in, use_L_in, and use_C_in.

Example

If the flag use_R_in = true, the value of R is computed as

R = R_min + y_R (R_max - R_min)

Extends from Buildings.Electrical.Interfaces.Load (Partial model for a generic load).

Parameters

Connectors

Modelica definition

Buildings.Electrical.Interfaces.InductiveLoad

Partial model of an inductive load

Information

This is a model of a generic inductive load. This model is an extension of the base load model Buildings.Electrical.Interfaces.PartialLoad.

This model assumes a fixed power factor pf when the flag use_pf_in = false otherwise it uses the power factor specified by the input pf_in.

The power factor (either the input or the parameter) is used to compute the reactive power Q given the active power P

Q = P tan(arccos(pf))

Extends from Load (Partial model for a generic load).

Parameters

Connectors

Modelica definition

Buildings.Electrical.Interfaces.Load

Partial model for a generic load

Information

This model represents a generic load that can be extended to represent either a DC or an AC load.

The model has a single generalized electric terminal of type Buildings.Electrical.Interfaces.Terminal that can be redeclared. The generalized load is modeled as an impedance whose value can change. The value of the impedance can change depending on the value of the parameter mode, which is of type Buildings.Electrical.Types.Load:

Conventions

It is assumed that the power P of the load is positive when produced (e.g., the load acts like a source) and negative when consumed (e.g., the source acts like a utilizer).

Linearized models

The model has a Boolean parameter linearized that by default is equal to false. When the power consumption of the load is imposed, this introduces a nonlinear equation between the voltage and the current of the load. This flag is used to select between a linearized version of the equations or the original nonlinear ones.
When the linearized version of the model is used, the parameter V_nominal has to be specified. The nominal voltage is needed to linearize the nonlinear equations.

Note: A linearized model will not consume the nominal power if the voltage at the terminal differs from the nominal voltage.

Parameters

Connectors

Modelica definition

Buildings.Electrical.Interfaces.PartialBaseTwoPort

Model of a generic two port component

Information

This model declares connectors for electrical components with two terminals.

Parameters

Connectors

Modelica definition

Buildings.Electrical.Interfaces.PartialConversion

Model representing a generic two port system for conversion

Information

This model extends the base class Buildings.Electrical.Interfaces.PartialTwoPort model and declares the variables v_p and i_p that represents the voltage and the current at the terminal_p, and the variables v_n and i_n that represents the voltage and the current at the terminal_n. These variables are used in conversion models such as transformers and AC/DC converters.

Extends from Buildings.Electrical.Interfaces.PartialTwoPort (Model of a generic two port component with phase systems).

Parameters

Connectors

Modelica definition

Buildings.Electrical.Interfaces.PartialPV

Base model for a PV system

Information

Partial model of a simple photovoltaic array.

This model computes the power as P=A   f_act   η   G, where A is the panel area, f_act is the fraction of the aperture area, η is the panel efficiency and G is the total solar irradiation.

Note: This model takes as input the total solar irradiation on the panel. This has to be computed converting the incoming radiation to take tilt and azimuth into account.

The electrical connector is a general electrical interface.

Extends from Buildings.Electrical.Interfaces.PartialPvBase (Partial model with basic parameters for PVs).

Parameters

Connectors

Modelica definition

Buildings.Electrical.Interfaces.PartialPVOriented

Base model of a PV system with orientation

Information

Partial model of a simple photovoltaic array.

This model takes as an input the direct and diffuse solar radiation from the weather data bus.

This model computes the power as P=A   f_act   η   G, where A is the panel area, f_act is the fraction of the aperture area, η is the panel efficiency and G is the total solar irradiation, which is the sum of direct and diffuse irradiation. The model takes into account the location and the orientation of the PV panel, specified by the surface tilt, latitude and azimuth.

Extends from Buildings.Electrical.Interfaces.PartialPvBase (Partial model with basic parameters for PVs).

Parameters

Connectors

Modelica definition

Buildings.Electrical.Interfaces.PartialPvBase

Partial model with basic parameters for PVs

Information

This model contains the minimum set of parameters necessary to describe a PV system. The model defines also an output P for the power generated by the PVs.

Parameters

Connectors

Modelica definition

Buildings.Electrical.Interfaces.PartialTwoPort

Model of a generic two port component with phase systems

Information

This is a model of a component with two electric terminals. It represents a common interface that is extended by other models.

Extends from Buildings.Electrical.Interfaces.PartialBaseTwoPort (Model of a generic two port component).

Parameters

Connectors

Modelica definition

Buildings.Electrical.Interfaces.PartialWindTurbine

Partial model of a wind turbine with power output based on table as a function of wind speed

Information

Model of a wind turbine whose power is computed as a function of wind-speed as defined in a table.

Input to the model is the local wind speed. The model requires the specification of a table that maps wind speed in meters per second to generated power P_t in Watts. The model has a parameter called scale with a default value of one that can be used to scale the power generated by the wind turbine. The generated electrical power is

P = P_t scale

For example, the following specification (with default scale=1) of a wind turbine

  WindTurbine_Table tur(
    table=[3.5, 0;
           5.5,   100;
           12, 900;
           14, 1000;
           25, 1000]) "Wind turbine";

yields the performance shown below. In this example, the cut-in wind speed is 3.5 meters per second, and the cut-out wind speed is 25 meters per second, as entered by the first and last entry of the wind speed column. Below and above these wind speeds, the generated power is zero.

Extends from Buildings.Electrical.Interfaces.PartialWindTurbineBase (Base class for turbine model that contains basic parameters).

Parameters

Connectors

Modelica definition

Buildings.Electrical.Interfaces.PartialWindTurbineBase

Base class for turbine model that contains basic parameters

Information

This partial model contains the minimum set of parameters necessary to describe a wind turbine. The model defines also an output P for the power generated by the wind turbine.

Parameters

Connectors

Modelica definition

Buildings.Electrical.Interfaces.ResistiveLoad

Partial model of a resistive load

Information

This is a model of a generic resistive load. This model is an extension of the base load model Buildings.Electrical.Interfaces.PartialLoad.

Extends from Load (Partial model for a generic load).

Parameters

Connectors

Modelica definition

Buildings.Electrical.Interfaces.Source

Partial model of a generic source.

Information

This model represents a generic source.

In case the phase system has PhaseSystem.m > 0 and thus the connectors are over determined, the source can be selected to serve as reference point. The parameters potentialReference and definiteReference are used to define if the source model should be selected as source for the reference angles theta or not. More information about overdetermined connectors can be found in Olsson Et Al. (2008).

References

Hans Olsson, Martin Otter, Sven Erik Mattson and Hilding Elmqvist.
Balanced Models in Modelica 3.0 for Increased Model Quality.
Proc. of the 7th Modelica Conference, Bielefeld, Germany, March 2008.

Parameters

Connectors

Modelica definition

Buildings.Electrical.Interfaces.Terminal

Generalized electric terminal

Information

This connector represents a generalized electric terminal. The generalization is made possible by the replaceable package Buildings.Electrical.Interfaces.Terminal.PhaseSystem. The package PhaseSystem can be one of the packages contained in Buildings.Electrical.PhaseSystems. Using this approach allows to represent DC, single phase AC and multi phases balanced and unbalanced AC systems with the same connector.

This connector is compatible with the following Modelica libraries:

• Electric Power Library developed by Modelon, and
• Power Systems Library developed by Ruediger Franke (ABB).

The connector is overdetermined since the number of effort variables is higher than the number of flow variables. This happens when the phase system has a number of reference angles PhaseSystem.m > 0. The over-determined connectors are defined and used in such a way that a Modelica tool is able to remove the superfluous but consistent equations arriving at a balanced set of equations, based on a graph analysis of the connection structure. The models have to use ad-hoc constructs specified by the Modelica language to handle this situation. More information can be found in Olsson Et Al. (2008).

More details about the generalized electrical terminal can be found in Franke and Wiesmann (2014).

References

Hans Olsson, Martin Otter, Sven Erik Mattson and Hilding Elmqvist.
Balanced Models in Modelica 3.0 for Increased Model Quality.
Proc. of the 7th Modelica Conference, Bielefeld, Germany, March 2008.

Ruediger Franke and Hansjurg Wiesmann.
Flexible modeling of electrical power systems - the Modelica PowerSystems library.
Proc. of the 10th Modelica Conference, Lund, Sweden, March 2014.

Extends from Buildings.Electrical.Interfaces.BaseTerminal (Empty connector used by partial models).

Parameters

Contents

Modelica definition

Buildings.Electrical.Interfaces.VariableVoltageSource

Partial model of a generic variable voltage source.

Information

This model represents a generic variable voltage source. The model has a boolean flag use_V_in, when this flag is equal to true the voltage of the source is imposed by the input variable V_in. When the flag is equal to false the voltage source is equal to the parameter V.

In case the phase system adopted has PhaseSystem.m > 0 and thus the connectors are over determined, the source can be selected to serve as reference point. The parameters potentialReference and definiteReference are used to define if the source model should be selected as source for the reference angles or not. More information about overdetermined connectors can be found in Olsson Et Al. (2008).

References

Hans Olsson, Martin Otter, Sven Erik Mattson and Hilding Elmqvist.
Balanced Models in Modelica 3.0 for Increased Model Quality.
Proc. of the 7th Modelica Conference, Bielefeld, Germany, March 2008.

Extends from Buildings.Electrical.Interfaces.Source (Partial model of a generic source.).

Parameters

Connectors

Modelica definition

Buildings.Electrical.Interfaces.PartialAcDcParameters

Partial model that contains basic parameters for a DC/AC conversion system

Information

This model contains the minimum set of parameters necessary to describe an AC/DC converter.

Parameters

Modelica definition

Buildings.Electrical.Interfaces.PartialPluggableUnbalanced

Partial interface for unbalanced loads

Information

This record contains a set of parameters that are used when modeling three-phase unbalanced systems. The record contains three boolean flags that are used to determine which of the three-phase are connected to the network.

Parameters

Modelica definition