Delta-Connected Load
Three-phase load connected in a Delta pattern.
Description
The Delta-Connected Load unit simulates a three-phase delta connected load. Each phase of the load can include any combination of resistor (R), capacitor (C) and inductance coil (L) connected in series or parallel. The load is phase symmetrical, i.e. the resistance, capacitance and inductance values of all phases are the same.
The values of the components R, L and C can be specified either directly as resistance, inductance and capacitance, or through the values of nominal powers (i.e. at nominal voltage and frequency).
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If the block is parameterised directly via the values R, L and C, a three-element vector string of initial voltages for the capacitor and a three-element vector string of initial currents for the inductance coil are specified for initialisation.
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If the block is parameterised via rated power values, the initial voltage value, the initial voltage phase and the initial frequency are specified for initialisation. For example, if the load is connected directly to a three-phase voltage source, the initial values must be equal to the rms values of the line voltage, frequency and phase of this source. To set the initial voltage to zero, set the initial voltage to 0.
For certain combinations of R, L and C, for certain circuit topologies, set parasitic resistance or conductance values that help the simulation converge numerically. These parasitic terms ensure that the inductance coil has a small parallel resistive path and the capacitor has a small series resistance. When you parameterise the block in terms of rated powers, the rated power values do not take these small parasitic terms into account. The rated powers only represent the R, L and C values of the load itself.
Block parameterization
The following two tables list the block parameters for each component structure based on the selected parameterization option:
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By power rating.
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Component values directly.
*Based on rated power
| Component structure | Basic parameters | Parasitic parameters | Initial condition parameters |
|---|---|---|---|
R |
Nominal voltage Active power |
No |
No |
L |
Nominal voltage Rated frequency Inductive reactive power |
Parasitic parallel conductance |
Terminal voltage value Phase of terminal voltage Frequency |
C |
Rated voltage Rated frequency Capacitive reactive power |
Parasitic series resistance |
Terminal voltage value Phase of terminal voltage Frequency |
Series RL |
Nominal voltage Rated frequency Active power Inductive reactive power |
Parasitic parallel conductance |
Terminal voltage value Phase of terminal voltage Frequency |
Series RC |
Nominal voltage Rated frequency Active power Capacitive reactive power |
No |
Terminal voltage value Phase of terminal voltage Frequency |
Series LC |
Nominal voltage Rated frequency Inductive reactive power Capacitive reactive power |
Parasitic parallel conductance |
Terminal voltage value Phase of terminal voltage Frequency |
Series RLC |
Nominal voltage Rated frequency Active power Inductive reactive power Capacitive reactive power |
Parasitic parallel conductance |
Terminal voltage value Phase of terminal voltage Frequency |
Parallel RL |
Nominal voltage Rated frequency Active power Inductive reactive power |
No |
Terminal voltage value Phase of terminal voltage Frequency |
Parallel RC |
Nominal voltage Rated frequency Active power Capacitive reactive power |
Parasitic series resistance |
Terminal voltage value Phase of terminal voltage Frequency |
Parallel LC |
Nominal voltage Rated frequency Inductive reactive power Capacitive reactive power |
Parasitic series resistance |
Terminal voltage value Phase of terminal voltage Frequency |
Parallel RLC |
Nominal voltage Rated frequency Active power Inductive reactive power Capacitive reactive power |
Parasitic series resistance |
Terminal voltage value Phase of terminal voltage Frequency |
*Component values directly
| Component structure | Main parameters | Parasitic parameters | Initial condition parameters |
|---|---|---|---|
R |
Resistance |
No |
No |
L |
Inductance |
Parasitic parallel conductivity |
Initial inductance coil current [ Ia Ib Ic ] |
C |
Capacitance |
Parasitic series resistance |
Initial capacitor voltage [ Va Vb Vc ] |
Series RL |
Resistance Inductance |
Parasitic parallel conductivity |
Initial inductance coil current [ Ia Ib Ic ] |
Series RC |
Resistance Capacitance |
No |
Initial capacitor voltage [ Va Vb Vc ] |
Series LC |
Inductance Capacitance |
Parasitic parallel conductivity |
Initial inductance coil current [ Ia Ib Ic ] Initial capacitor voltage [ Va Vb Vc ] |
Series RLC |
Resistance Inductance Capacitance |
Parasitic parallel conductivity |
Initial inductance coil current [ Ia Ib Ic ] Initial capacitor voltage [ Va Vb Vc ] |
Parallel RL |
Resistance inductance |
No |
Initial inductance coil current [ Ia Ib Ic ] |
Parallel RC |
Resistance Capacitance |
Parasitic series resistance |
Initial capacitor voltage [ Va Vb Vc ] |
Parallel LC |
Inductance Capacitance |
Parasitic series resistance |
Initial inductance coil current [ Ia Ib Ic ] Initial capacitor voltage [ Va Vb Vc ] |
Parallel RLC |
Resistance Inductance Capacitance |
Parasitic series resistance |
Initial inductance coil current [ Ia Ib Ic ] Initial capacitor voltage [ Va Vb Vc ] |
Parameters
Main
parameterization - parameterization
by power (by default) | directly
Block parameterization:
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by power- values for the components R, L and C are set through the values of rated power at rated voltage and frequency. By default parameterization. -
directly- values for components R, L and C are set directly as resistance, inductance and capacitance.
Toggling the value of the Parameterization parameter resets the value of the Component structure parameter. First select the Parameterization parameter value and then Component structure. If you later switch the parameterization value, check the Component structure value and reselect it if necessary.
Component structure is a combination of R, L and C
R (By default) | L | C | Series RL | Series RC | Series LC | Series RLC | Parallel RL | Parallel RC | Parallel LC | Parallel RLC
Specifies the combination of resistor (R), capacitor (C) and inductance coil (L) connected in series or parallel.
Resistance - resistance
`1.0 ohms (by default)
Resistance of each resistor.
Dependencies
This parameter is only used when Specify component values directly of the Parameterization parameter is selected and a component structure including a resistor is selected.
Inductance - inductance
1e-3 Gn (by default).
The inductance of each coil.
Dependencies
This parameter is only used when Specify component values directly of the Parameterization parameter is selected and a component structure including an inductor is selected.
Capacitance - capacitance
1e-6 F (By default).
Capacitance of each capacitor.
Dependencies
This parameter is only used when Specify component values directly of the Parameterization parameter is selected and a component structure including a capacitor is selected.
Rated voltage - rated voltage
24e3 V (By default).
The voltage for which the load capacities are specified.
This parameter is only used when specifying values for rated power.
Dependencies
This parameter is only used when Specify by rated power is selected in the Parameterization parameter.
Rated electrical frequency - rated frequency
50 Hz (By default).
The frequency for which the load reactive powers are specified.
Dependencies
This parameter is only used when Specify by rated power is selected in the Parameterization parameter.
Real power is the total active power dissipated
1e3 W (By default).
The total active power dissipated by a three-phase load at rated voltage. The value must be greater than 0.
Dependencies
This parameter is only used when Specify by rated power is selected in the Parameterization parameter and a component structure including a resistor is selected.
Inductive reactive power - inductive reactive power
1e2 V*A (by default).
The total inductive reactive power consumed by a three-phase load at rated voltage. The value must be greater than 0.
Dependencies
This parameter is only used when Specify by rated power of the Parameterization parameter is selected and a component structure including an inductor is selected.
Capacitive reactive power - total capacitive reactive power
-1e2 V*A (by default).
The total capacitive reactive power consumed by a three-phase load at rated voltage. The value must be less than 0.
Dependencies
This parameter is only used when Specify by rated power of the Parameterization parameter is selected and a component structure including a capacitor is selected.
Parasitics
Parasitic series resistance, Ohm - parasitic series resistance
`0 Ohm (by default)
Represents small parasitic effects. The parameter value corresponds to the value of series resistance added to all capacitor instances in the load.
Parasitic parallel conductance, 1/Ohm - Parasitic parallel conductance
0 1/Ohm (by default).
Represents small parasitic effects. The parameter value corresponds to the parallel conductance value added to all inductance coil instances in the load.
If you set the Component structure parameter to one of the Series RL, Series LC or Series RLC values, the parasitic parallel conductance is connected through the full branch of the block.