Capacitor banks can be used to offset the inductive characteristics (lagging power factor) of the PV plant and to help achieve the leading power factor requirements defined in an interconnection agreement. Capacitor banks are simulated within the power flow model only when the Plant Control Mode is set to Real and Reactive Power Control.
When the plant is modeled in Real and Reactive Power Control mode, capacitor banks may be sized as follows:
- No Capacitor Bank
- User Specified Capacitor Bank Size
- Automatically Sized Capacitor Bank (to Minimize the Cap Bank Size)
- Automatically Sized Capacitor Bank (to Minimize Reactive Power Compensation Losses)
No Capacitor Bank
Under this scenario, a capacitor bank is not used in the power flow model.
User Specified Capacitor Bank Size
Under this scenario, the user may specify the total capacitor bank size in kVAR as well as the number of capacitor bank stages. The total capacitor bank is divided equally into the number of stages. For example, a 4500kVAR capacitor bank with three stages is divided into three 1500kVAR capacitor banks. Each stage may be independently switched into the system by the plant controller.
Note: More stages allow for more granular capacitor bank switching by the plant controller. However, more stages will also generally cost more due to the additional switching equipment.
Automatically Sized Capacitor Bank (to Minimize the Cap Bank Size)
Under this scenario, the capacitor bank is sized to meet the leading power factor requirement at the point of delivery at maximum power. This is computed assuming the inverters are being operated at their maximum leading power factor. Once the minimum capacitor bank size is determined (in kVAR), the capacitor bank is upsized to the next available market rating and the number of stages are computed. See below for HST assumed available sizes and stages.
Automatically Sized Capacitor Bank (to Minimize Reactive Power Compensation Losses)
Under this scenario, the capacitor bank is sized to the meet the leading power factor requirement at the point of delivery at maximum power. But this is computed assuming the inverters are being operated at unity power factor. Once the minimum capacitor bank size is determined (in kVAR), the capacitor bank is upsized to the next available market rating and the number of stages are computed. See below for HST assumed available sizes and stages.
Capacitor Bank Available Size Ranges
| Max Stage Size (kVAR) | Max No. of Stages |
| 150 | 2 |
| 300 | 3 |
| 750 | 4 |
| 1500 | 4 |
| 3000 | 4 |
| 6000 | 5 |
| 9000 | 6 |
| 12000 | 6 |
| 15000 | Inf |