© 2020 SEL

New Advancements in Solar Grid Controllers

Brian Waldron and Bryan FazzariSchweitzer Engineering Laboratories, Inc.

PV Generation Is Expanding Rapidly

• Residential• Commercial• Utility scale

PV Generation in Different Applications

• 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

• Voltage• Reactive power• Frequency response

PV Supported Ancillary Services

• 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

• Irradiance • Ambient temperature• Cloud cover

Primary Forecasting Factors

• 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

Questions?