Wye-Connected Load
Three-phase load connected in a Star pattern.
Description
The Wye-Connected Load unit simulates a three-phase load connected in a Star pattern. Each phase of the load can include any combination of resistor ( ), capacitor ( ) and inductance coil ( ) 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 , and can be specified either directly as resistance, inductance and capacitance or through the values of the rated powers (i.e. at rated voltage and frequency).
-
If the block is parameterised directly via the values , and , 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.
-
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.
Block parameterization
The following two tables list the block parameters for each component structure based on the selected parameterization option:
-
By power rating.
-
Component values directly.
*By power rating
| Component structure | Basic parameters | Parameters of initial conditions |
|---|---|---|
|
Nominal voltage Active power |
No |
|
Nominal voltage Rated frequency Inductive reactive power |
Terminal voltage value Phase of terminal voltage Frequency |
|
Nominal voltage Rated frequency Capacitive reactive power |
Terminal voltage value Phase of terminal voltage Frequency |
Series RL |
Nominal voltage Rated frequency Active power Inductive reactive power |
Terminal voltage value Phase of terminal voltage Frequency |
Series RC |
Nominal voltage Rated frequency Active power Capacitive reactive power |
Terminal voltage value Phase of terminal voltage Frequency |
Series LC |
Nominal voltage Rated frequency Inductive reactive power Capacitive reactive power |
Terminal voltage value Phase of terminal voltage Frequency |
Series RLC |
Nominal voltage Rated frequency Active power Inductive reactive power Capacitive reactive power |
Terminal voltage value Phase of terminal voltage Frequency |
Parallel RL |
Nominal voltage Rated frequency Active power Inductive reactive power |
Terminal voltage value Phase of terminal voltage Frequency |
Parallel RC |
Nominal voltage Rated frequency Active power Capacitive reactive power |
Terminal voltage value Phase of terminal voltage Frequency |
Parallel LC |
Nominal voltage Rated frequency Inductive reactive power Capacitive reactive power |
Terminal voltage value Phase of terminal voltage Frequency |
Parallel RLC |
Nominal voltage Rated frequency Active power Inductive reactive power Capacitive reactive power |
Terminal voltage value Phase of terminal voltage Frequency |
*Component values directly
| Component structure | Basic parameters | Parameters of initial conditions |
|---|---|---|
|
Resistance |
No |
|
Inductance |
Initial inductance coil current [ Ia Ib Ic ] |
|
Capacitance |
Initial capacitor voltage [ Va Vb Vc ] |
Series RL |
Resistance Inductance |
Initial inductance coil current [ Ia Ib Ic ] |
Series RC |
Resistance Capacitance |
Initial capacitor voltage [ Va Vb Vc ] |
Series LC |
Inductance Capacitance |
Initial inductance coil current [ Ia Ib Ic ] Initial capacitor voltage [ Va Vb Vc ] |
Series RLC |
Resistance Inductance Capacitance |
Initial inductance coil current [ Ia Ib Ic ] Initial capacitor voltage [ Va Vb Vc ] |
Parallel RL |
Resistance inductance |
Initial inductance coil current [ Ia Ib Ic ] |
Parallel RC |
Resistance Capacitance |
Initial capacitor voltage [ Va Vb Vc ] |
Parallel LC |
Inductance Capacitance |
Initial inductance coil current [ Ia Ib Ic ] Initial capacitor voltage [ Va Vb Vc ] |
Parallel RLC |
Resistance Inductance Capacitance |
Initial inductance coil current [ Ia Ib Ic ] Initial capacitor voltage [ Va Vb Vc ] |
Parameters
Main
parameterization - parameterization
by power (by default) | directly
Block parameterization:
-
by power- values for the components , and are set through the values of rated power at rated voltage and frequency. By default parameterization. -
directly- values for components , and 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 ( ), capacitor ( ) and inductance coil ( ) connected in series or parallel.
Resistance - resistance
`1.0 ohm (by default)
Resistance of each resistor.
Inductance - inductance
1e-3 Gn (by default)
The inductance of each coil.
Capacitance - capacitance
1e-6 F (By default)
Capacitance of each capacitor.
Rated voltage - rated voltage
`24e3 V (by default)
The voltage for which the load capacities are specified.
Rated electrical frequency - rated frequency
50 Hz (By default)
The frequency for which the load reactive powers are specified.
Real power - total active power dissipation
1e3 W (by default)
The total active power dissipated by a three-phase load at rated voltage. The value must be greater than 0.
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.
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.
Initial values
Initial value of current through inductors, [Ia Ib Ic] - initial values of coil currents
zeros(3) (by default)
Initial values of currents through inductor coils.
Initial value of voltage across capacitors, [Va Vb Vc] - initial values of voltage across capacitors
zeros(3) (by default)
Initial values of voltage across capacitors.
Initial value of terminal voltage magnitude, V - initial value of terminal voltage magnitude
`24e3 V (by default).
Initial value of terminal voltage magnitude.
Initial value of terminal voltage angle, deg - initial value of terminal voltage phase
0.0 (By default)
Initial value of terminal voltage phase.
Initial value of frequency, Hz - initial value of frequency
0.0 (by default)
Initial value of frequency.
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 instances of inductance coils 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.