This is a two-phase delta load model. The model allows the user to represent active and reactive power being consumed between two phases.
The user needs to input the active (P_ab) and reactive (Q_ab) powera consumed between phases one and two (A and B).
In addition, the model allows the load to be represented as constant power, or as a ZIP model. In the first approach, the power consumed between the two phases is kept constant throughout simulation. The latter approach allows the load to be represented as a sum of three terms: constant impedance, constant current and constant power. This means that, depending on voltage levels supplied, the load will consume a different power value.