1. Composite Load Model with Distributed Generation (CMPLDWG)
Irina Green
California ISO
WECC Load Modeling and Validation Group Meeting
October 2017

2. Composite Load Model
When voltage is below specified values, the model trips fractions of each motor, electronic and static load
The fractions of load that are tripped and voltages at which they are tripped are specified by the user
Distributed generation was assumed having unity power factor
DG also have settings at which voltage and frequency they may be tripped or reconnected

3. Parameters of DG Part of Composite Load Model
Currently, in GE PSLF cmpldwg model, only PV can be modeled
Simplified model
No time-dependent component
Similar to PVD1 model, but simplified
Less options by the user

4. GE PSLF CMPLDWG Model, DG Part

5. PVD1 Model – Distributed Solar PV
More detailed model than the DG part of composite load model
No time-dependent component
More detailed voltage and frequency tripping response curves
Reactive or active current priority
Modeled as generation at power flow buses

6. DER_A Model – Work in Progress
Reduced version of generic large PV plant model
Frequency and voltage control emulation, with asymmetric dead-band. The voltage control only allows for proportional control.
Allows for constant power factor and constant Q-control
Intended to use as aggregated, allows partial tripping
Allows for modeling ramp-rate limits on the real-power recovery following a fault or during primary-frequency response, and also models a basic current limit with P/Q priority options
May also represent battery storage, however without emulation of charge or discharge
More detailed than DG portion of the cmpldwg model and than PVD1 model, and requires more parameters than these models

7. DER_A Model

8. DER_A Model

9. Issues with CMPLDWG Model
Model may become unstable if output of distributed generation is larger that load and the load is small
On this bus, load is 2.4 MW, DG is 9.3 MW
When DG was modeled with the PVD1 model and the load was modeled without DG, the no-disturbance run was flat
With negative net load, composite load was unstable if the gross load was less than 5 MW

10. New Models – Options
Approve composite load model with distributed generation as it exists in GE PSLF?
Wait for the DER_A model until is may be used as a module in the composite load model?
Which parameters to use with the DER_A model