What you are describing is the complex bus power injection, not apparent power
(which is just the magnitude of the complex power). And yes, the power in MVA
is simply the per unit value times the MVA base (baseMVA). Kirchhoff’s current
law (KCL) implies that all power injected into a bus (or leaving a bus) must
sum to zero. In MATPOWER, that includes generation (Pg), load (Pd), connected
branches (Pf), and shunts, and likewise for reactive power. So I believe your
understanding is correct.
Ray
On Apr 16, 2020, at 7:04 PM, yangyang
<[email protected]<mailto:[email protected]>> wrote:
Dear Prof Ray Zimmerman,
In Matpower Technote 2,AC Power Flows, Generalized OPF Costs and their
Derivatives using Complex Matrix Notation, we can find that bus appearant power
is Sbus = Vbus .* conj(Ibus),where Ibus = Ybus* Vbus, and Vbus =
Vm.*exp(Va*180/pi). But in cases, it seems that the results will be Sbus in per
unit and it is hard to find its relationship with bus power in runpf() results.
In my understanding, the nominal appearant power might be Sbus_nom=baseKVA.*
Sbus, where Sbus is the appearant power in per unit mentioned above. And in
power flow results, it should be the Pf, Pt, Qf, Qt results in branch data
plus/subtracts (Pg -Pd) and (Qg - Qd) in bus and generator data. Is my
understanding correct? Hoping that you can help me with it, thank you for your
time.
