Buildings.Electrical.Transmission.Functions
Package that contains functions to compute cable properties
Information
This package contains various functions that are used to compute cable properties and select the default cable during automatic parametrization.
Extends from Modelica.Icons.Package (Icon for standard packages).
Package Content
Name | Description |
---|---|
R_AC_correction | This function computes the correction factor of the DC resistance for AC systems at 60 Hz |
computeGMD | This function computes the geometric mean distance of a three-phase transmission line |
computeGMR | This function computes the geometric mean radius of a cable with 1 to 4 conductors |
selectCable_low | This function is used to automatically select the type of cable for low voltages |
selectCable_med | This function is used to automatically select the type of cable for medium voltages |
selectVoltageLevel | This function computes the voltage level (low, medium or high) given the nominal voltage |
Validation |
Buildings.Electrical.Transmission.Functions.R_AC_correction
This function computes the correction factor of the DC resistance for AC systems at 60 Hz
Information
This function computes a correction factor for adapting the DC resistance when working with AC voltages. The correction factor assumes f = 60 Hz.
The correction is based on the type of cabel (AWG or kcmil) and the material.
Type (AWG or kcmil) | Material | Correction factor |
---|---|---|
1/0 | Aluminium | 1.0 |
2/0 | Aluminium | 1.001 |
3/0 | Aluminium | 1.001 |
4/0 | Aluminium | 1.001 |
250 | Aluminium | 1.002 |
300 | Aluminium | 1.003 |
350 | Aluminium | 1.004 |
400 | Aluminium | 1.005 |
500 | Aluminium | 1.007 |
600 | Aluminium | 1.010 |
700 | Aluminium | 1.013 |
750 | Aluminium | 1.015 |
800 | Aluminium | 1.017 |
1000 | Aluminium | 1.026 |
1250 | Aluminium | 1.040 |
1500 | Aluminium | 1.058 |
1750 | Aluminium | 1.079 |
2000 | Aluminium | 1.100 |
2500 | Aluminium | 1.142 |
Type (AWG or kcmil) | Material | Correction factor |
---|---|---|
1/0 | Copper | 1.0 |
2/0 | Copper | 1.001 |
3/0 | Copper | 1.002 |
4/0 | Copper | 1.004 |
250 | Copper | 1.005 |
300 | Copper | 1.006 |
350 | Copper | 1.009 |
400 | Copper | 1.011 |
500 | Copper | 1.018 |
600 | Copper | 1.025 |
700 | Copper | 1.034 |
750 | Copper | 1.039 |
800 | Copper | 1.044 |
1000 | Copper | 1.067 |
1250 | Copper | 1.102 |
1500 | Copper | 1.142 |
1750 | Copper | 1.185 |
2000 | Copper | 1.233 |
2500 | Copper | 1.326 |
Inputs
Type | Name | Default | Description |
---|---|---|---|
String | size | Size of the commercial cable (AWG or kcmil) | |
Material | material | Material of the cable |
Outputs
Type | Name | Description |
---|---|---|
Real | correction | Correction factor |
Modelica definition
Buildings.Electrical.Transmission.Functions.computeGMD
This function computes the geometric mean distance of a three-phase transmission line
Information
This function computes the Geometric Mean Distance of a cable.
The GMD is computed as
GMD = (d1 d2 d3)1/3,
where d1, d2, and d3 are the distances between the conductors.
Inputs
Type | Name | Default | Description |
---|---|---|---|
Length | d1 | Distance between conductors [m] | |
Length | d2 | d1 | Distance between conductors [m] |
Length | d3 | 2*d1 | Distance between conductors [m] |
Outputs
Type | Name | Description |
---|---|---|
Length | GMD | Geometric Mean Distance [m] |
Modelica definition
Buildings.Electrical.Transmission.Functions.computeGMR
This function computes the geometric mean radius of a cable with 1 to 4 conductors
Information
This function computes the Geometric Mean Radius (GMR) of a cable.
The GMR is computed as follow, depending on the number of conductors N that are part of the cable, and the diamater of the conductor d.
Equation | Condition |
---|---|
0.7788 (d/2) | N = 1 |
d1/2 | N = 2 |
d2/3 | N = 3 |
d2/3 | N = 4 |
Inputs
Type | Name | Default | Description |
---|---|---|---|
Length | d | Diameter of the conductor [m] | |
Integer | N | 1 | Number of conductors |
Outputs
Type | Name | Description |
---|---|---|
Length | GMR | Geometric Mean Radius [m] |
Modelica definition
Buildings.Electrical.Transmission.Functions.selectCable_low
This function is used to automatically select the type of cable for low voltages
Information
This function selects the default cable for a low voltage transmission line.
The function takes as inputs the nominal voltage Vnominal and the nominal power Pnominal. It computes the maximum current current that can flow through the cable as
IMAX = SF Pnominal / Vnominal,
where SF is the safety factor. By default the safety factor is equal to 1.2.
Using IMAX, the function selects the smallest cable that has an ampacity higher than IMAX. The cables are selected from Buildings.Electrical.Transmission.LowVoltageCables.
Inputs
Type | Name | Default | Description |
---|---|---|---|
Power | P_nominal | 0 | Rated power [W] |
Voltage | V_nominal | 0 | Rated voltage [V] |
Outputs
Type | Name | Description |
---|---|---|
Generic | cable | Cable |
Modelica definition
Buildings.Electrical.Transmission.Functions.selectCable_med
This function is used to automatically select the type of cable for medium voltages
Information
This function selects the default cable for a medium voltage transmission line.
The function takes as inputs the nominal voltage Vnominal and the nominal power Pnominal. It computes the maximum current current that can flow through the cable as
IMAX = SF Pnominal / Vnominal,
where SF is the safety factor. By default the safety factor is equal to 1.2.
Using IMAX, the function selects the smallest cable that has an ampacity higher than IMAX. The cables are selected from Buildings.Electrical.Transmission.MediumVoltageCables.
Inputs
Type | Name | Default | Description |
---|---|---|---|
Power | P_nominal | 0 | Rated power [W] |
Voltage | V_nominal | 0 | Rated voltage [V] |
Outputs
Type | Name | Description |
---|---|---|
Generic | cable | Cable |
Modelica definition
Buildings.Electrical.Transmission.Functions.selectVoltageLevel
This function computes the voltage level (low, medium or high) given the nominal voltage
Information
This function computes the voltage level for a given voltage. The computation is as follows:
Condition | Voltage Level |
---|---|
0 ≤ V < 1 kV | Low voltage |
1 kV ≤ V < 50 kV | Medium voltage |
V ≥ 50 kV | HIgh voltage |
Inputs
Type | Name | Default | Description |
---|---|---|---|
Voltage | V | Nominal voltage [V] |
Outputs
Type | Name | Description |
---|---|---|
VoltageLevel | level | Type of voltage level |