© 2020 SEL
New Advancements in Solar Grid Controllers
Brian Waldron and Bryan FazzariSchweitzer Engineering Laboratories, Inc.
• Set point• Closed-loop control• VAR control• PF control• Voltage control
Standard PV Controller Features Today
• PPC communicates with inverters
• PPC communicates with PCC
PV Plant Controller Architecture
Plant Controller
Distribution Grid
PCC
Meter
• Time-shifting generation• Charging battery when availability is high• Discharging when PV panels are unable to generate• Discharging when energy price is high
Solar and Storage Integration
• Storage output smoothing• Use storage to maintain PCC output• Accounts for intermittency of PV panels• Increases consistency and reliability
Solar and Storage Integration
• Localized peak shaving• Reduce peak cost for load owner• Reduce stress on distribution system
Solar and Storage Integration
ISOs require separate Meter and Generation IDs for PV and storage sites unless the generation site provides forecasting data
Hybrid Generation and Market Integration
PCCMeter
PV Storage
Transmission Line
PCCMeter
PV Storage
Transmission Line
PCCMeter
• Forecasts fit into two categories Next hour (5 minutes to 6 hours)
Next day (6 hours to 24+ hours)
• ISOs charge generation customers forecasting feesper MWh
• Other solar generation sites are not required to generate forecasting data
Forecasting Power Production
Next-hour forecasting• Physical: real-time measurements processed with
model information from inverter vendor• Statistical: use historical output to create a model for
data output and use real-time measurements based on historical performance
Forecasting Next-Hour Methods
• Sky imaging• Process satellite image• Measure cloud direction• Measure cloud speed
Tracking Weather Patterns
• Data logging is a standard feature• PPC controller has all inverter data• Compare inverter output• Identify differences between inverters• Recognize patterns in communications outages
Data Analytics in PV Plants
• Purchase power agreements• Market regulations• Currently do not allow for economic or operation
incentives to be gained from many of these potential technologies
Economic Policy SignificantlyAffects PPC Technology