Monitoring Platforms: What Does Your PV System Need? A SCADA System or a DAS?

By K.C. Radford

Charlotte, NC – May 3,  2018

The implementation of SCADA and DAS systems has become standard practice in the solar industry and has become the primary tool for system operators to assess system performance and identify operational issues.

Identifying which monitoring platform to employ for your PV system and portfolio is key to setting up and monitoring performance. Oversight of the technical health of a portfolio is key to maximizing energy production and asset longevity.

Data Acquisition Systems (DAS) are typically third-party cloud based platforms with sensing and datalogging devices integrated into the design of the system. The DAS dataloggers serve as the heart of the communications network on the system, collecting data from all the components, including, the inverters, the weather station, the meter, the system protection devices, and the trackers. This data is then exported to the internet-based provider to be processed and accessed via the web based application.

Advantages of a DAS system:

  • Simple system design.
  • Provides easy remote access to assess system performance.
  • Designed for implementation on PV systems.
  • Easily implemented on multiple system designs.
  • Easily scales with system size.
  • Less expensive to implement than SCADA systems.

Disadvantages of a DAS

  • Real time data delays of between 5-15 min.
  • Does not typically include the ability to control any system components.
  • Has limitations with regard to complex and unique system designs.

Supervisory Control and Data Acquisition (SCADA) systems are typically custom control and data acquisition systems that utilize technology and software developed for use in substations by utilities. These systems are typically housed on a computer located within a substation control house, at the point of the interconnection substation. SCADA systems function as the brain of the system, collecting data from all the equipment and adjusting system setpoints in response to control signals from the system operator or utility. The implementation of SCADA to control PV systems is typically reserved for systems that are connected to the utility transmission system via a substation. SCADA systems allow for the control and operations of the PV system along with the substation and can meet several of the regulatory requirements of the system. SCADA systems allow the PV system to adjust to command signals from the utility and conduct operations such as curtailing power output, providing reactive power support and adjusting ramp rates for inverters.

Advantages of a SCADA system:

  • Robust, self-contained.
  • Allows for real-time control of the system to optimize performance.
  • Provides high resolution data for performance and event analysis.
  • Allows for complex operations schemes to take advantage of unique market opportunities.
  • Optimized for complex and large systems.

Disadvantages of a SCADA:

  • Can be difficult to implement remote control or monitoring.
  • Not all SCADA system are optimized for the needs of PV plants.
  • Complex SCADA systems can represent a significant cost to projects.
  • Specially trained and qualified personnel may be required to operate.

Some system integrators are developing somewhat of a hybrid DAS system that incorporates a Real Time Automation Controller (RTAC) into systems that would otherwise not include control elements. This allows for remote control of the equipment and adjustment of setpoints remotely. These designs are non-typical but can be very useful in certain applications. Alternatively, several system owners with SCADA systems have found it beneficial to install a DAS system as an alternative, to access the performance data from the system when access via the SCADA proves difficult.

What does your PV System need? The specific requirements of your system design and interconnection requirements will ultimately determine if a SCADA or DAS system should be implemented. Radian has significant experience integrating multiple variations of both DAS a

nd SCADA system in to our LENS™ asset management platform.

What if your portfolio of projects has both DAS and SCADA systems? Don’t fret. Radian’s asset management platform LENS™ has a lot of experience in aggregating portfolios that have both DAS and SCADA system onto a single dashboard. LENS™ allows for greater transparency by creating a single point of reference for your project documents, ticketing & tasks and monitoring.

Want better visibility into your asset performance & identification of key trends with automated data acquisition & data quality measures? Contact us to learn more about LENS™ or to talk with our Technical Asset Management Advisors. 415-901-3430