A shunt connected element such as a capacitor or inductor is modeled as a ﬁxed impedance to ground at a bus. The admittance of the shunt element at bus is given as
and denotes the vector of shunt admittances at all buses. The parameters and are speciﬁed in columns GS (5) and BS (6), respectively, of row of the bus matrix as equivalent MW (consumed) and MVAr (injected) at a nominal voltage magnitude of 1.0 p.u and angle of zero.
A shunt element can also be used to model a constant impedance load and, though correctly, Matpower does not currently report these quantities as “load”.