Implement three-phase parallel RLC load with selectable connection
The Three-Phase Parallel RLC Load block implements a three-phase balanced load as a parallel combination of RLC elements. At the specified frequency, the load exhibits a constant impedance. The active and reactive powers absorbed by the load are proportional to the square of the applied voltage.
Only elements associated with nonzero powers are displayed in the block icon.
The connection of the three phases. Select one of the following four connections:
Neutral is grounded.
Neutral is not accessible.
Neutral is made accessible through a fourth connector.
Three phases connected in delta
The block icon is updated according to the load connection.
The nominal phase-to-phase voltage of the load, in volts RMS (Vrms).
The nominal frequency, in hertz (Hz).
The three-phase active power of the load, in watts (W).
The three-phase inductive reactive power QL, in vars. Specify a positive value, or 0.
The three-phase capacitive reactive power QC, in vars. Specify a positive value, or 0.
Branch voltages to measure the three
voltages across each phase of the Three-Phase Parallel RLC Load block
terminals. For a Y connection, these voltages are the phase-to-ground
or phase-to-neutral voltages. For a delta connection, these voltages
are the phase-to-phase voltages.
Branch currents to measure the three
total currents (sum of R, L, C currents) flowing through each phase
of the Three-Phase Parallel RLC Load block. For a delta connection,
these currents are the currents flowing in each branch of the delta.
Select Branch voltages and currents to measure the three voltages and the three currents of the Three-Phase Parallel RLC Load block.
Place a Multimeter block in your model to display the selected measurements during the simulation. In the Available Measurements list box of the Multimeter block, the measurements are identified by a label followed by the block name.
Y(grounded): Uag, Ubg, Ucg
Y(floating): Uan, Ubn, Ucn
Y(neutral): Uan, Ubn, Ucn
Delta: Uab, Ubc, Uca
Y(grounded): Ia, Ib, Ic
Y(floating): Ia, Ib, Ic
Y(neutral): Ia, Ib, Ic
Delta: Iab, Ibc, Ica
The parameters on this tab are used by the Load Flow tool of the Powergui block. These load flow parameters are used for model initialization only, they have no impact on the block model and on the simulation performance.
Specify the load type.
If you select
constant Z, the load
impedance is determined from the nominal phase-to-phase voltage Vn,
active power P, and reactive power (QL-QC) specified on the Parameters tab
of the block dialog box. During the load flow solution, the impedance
is kept constant. The effective P and Q are therefore varying proportionally
to the square of the bus voltage computed by the Load Flow tool.
If you select
constant PQ, the active
power P and reactive power Q are kept constant and equal to the values
specified on the Parameters tab of the block
dialog box. When you apply the load flow solution to the model (by
clicking the Apply button of the Load Flow
tool), the Nominal phase-to-phase voltage Vn parameter
on the Parameters tab is automatically adjusted
to the phase-to-phase bus voltage computed by the Load Flow tool.