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PQ Load (3-phase)
Three-phase constant-PQ load — single component carrying both an EMT constant-impedance Y-connected R+L per phase AND a load-flow PL/QL row. The EMT side computes the equivalent admittance Y = (P − jQ)/V_LL² at the rated nominal voltage and stamps a Y-connected R+L to ground per phase; actual P/Q drawn in EMT then varies as |V|² around V_nom. The load-flow side stays a textbook constant-power model. The two converge exactly when the solved bus voltage equals v_nom_v.
Category: Three-Phase / Passive
Keywords: 3-phase, 3-ph, 3 ph, 3ph, three, three-phase, three phase, phase, ph, PQ, load, consumer, MW, MVAr, load flow, loadflow, constant power, constant impedance, EMT, P, Q
Ports
| Name | Direction | Value type | Notes |
|---|---|---|---|
bus | electrical_3ph | double |
Parameters
Config
| Name | Label | Type | Default | Units | Description |
|---|---|---|---|---|---|
p_mw | P (MW) | double | 10 | — | 3-phase real-power demand at V_nom (MW). Drives the load-flow PL column and the EMT admittance Y = (P − jQ)/V_LL². Positive = drawn from the bus. |
q_mvar | Q (MVAr) | double | 3 | — | 3-phase reactive-power demand at V_nom (MVAr). Positive = inductive (L > 0); negative = capacitive. Drives QL and Im(Y) in EMT. |
v_nom_v | V nom (LL) | double | 13800 | — | Line-to-line RMS voltage at which (P, Q) are specified. EMT uses Y_phase = (P − jQ) / V_LL²; EMT and PF match exactly when |V| = V_nom, otherwise EMT draw varies as |V|². |
f_rated_hz | f rated | double | 60 | — | System frequency (Hz). Used for the siemens → henries conversion of the reactive admittance: L = X / (2πf). |
measure_current | Measure current | enum (Off / On) | 0 | — | Emit per-phase load currents (positive = into the load). Names on the Current Monitoring tab; blank skips a phase. |
Current Monitoring
| Name | Label | Type | Default | Units | Description |
|---|---|---|---|---|---|
i_name_a | Current name A | string | Ia | — | Observable id for Phase A load current. |
i_name_b | Current name B | string | Ib | — | Observable id for Phase B load current. |
i_name_c | Current name C | string | Ic | — | Observable id for Phase C load current. |
Observables
| Signal | Type | Default name | Enable | Description |
|---|---|---|---|---|
branchCurrent_a | signal | from i_name_a | measure_current | Phase A load current (A). Positive = current drawn from the bus into the load. |
branchCurrent_b | signal | from i_name_b | measure_current | Phase B load current (A). |
branchCurrent_c | signal | from i_name_c | measure_current | Phase C load current (A). |
Used in samples
Implemented in C++ class SimCompElecPqLoad3ph (components/electrical/sim_comp_elec_pq_load_3ph/sim_comp_elec_pq_load_3ph.h).