Electrical supply grids are having to become smarter so that they can self-optimise and improve their overall efficiency. Steinar Sande explores how embedding controllers around a grid can help measure power flows, demand requirements, etc, and leads to real-time management for best performance.
Wind, solar, tidal and hydropower generation facilities are becoming increasingly mainstream as generating companies are developing alternatives to traditional fossil fuels and nuclear power. Integrating these assets into the supply grid has presented several new challenges, often based on the fact that generating capacity is based on variable wind speed, sun level and water flow. As a result, engineers are also looking for new ways to manage power flows, peak demands, etc.
Within a grid it is usual that the various power generation sites are somewhat distant from one another and also some distance from the controlling operations centre. Therefore, control of the generating site must be achievable, remotely.
Raima has worked with a number of partner companies including LocalGrid Technologies, from Mississauga, ON and global company National Instruments to develop a complete microgrid control solution.
Energy demand is growing, both in the developed and the developing world, as populations grow and urbanise, and economic activity matures. Therefore, power supplies more than ever need to be reliable, affordable and increasingly incorporate renewable energy sources.
Some electricity grids are 75 or even 100 years old; others have been poorly maintained over many years, so find it difficult to meet the ever-increasing demand. Therefore, the issues can be expressed as a need to improve the capability of electrical grids to meet demand, which is predicted to continue growing for many years.
Options for a large-scale rebuilding of the power delivery infrastructure are limited; instead, innovative new technologies that convert existing grids into smart flexible solutions that can be implemented over time seem to be the way forward.
The partner companies are addressing this requirement by creating a complete microgrid control solution, based on NI CompactRIO hardware. The software runs on embedded controllers deployed in key points in the grid, distributing intelligence and decentralised decision-making out to the remote devices and distributed energy resources.
The objective is to create a platform for securely managing power flow, peak load, distributed generation, and other energy assets using real-time data collection, analytics, and control on a distributed intelligence network, pushing the decision-making out into the network, increasing the system’s fault-tolerance. This solution is in fact a scalable architecture, which can be deployed on both large and small grids, and is able to grow (or contract) with the needs of the operator.
Each device deployed to the network exhibits certain key features including high-speed data capture, high-speed logging, event detection, protocol translation (including Modbus, DNP3, IEC61850, and other custom protocols), custom control processing, custom control algorithm deployment processing, built-in security, and remote device management.
In addition, the open architecture allows expansion of the system and ensures interoperability.
Fundamental to the design is embedded database technology. The core of the solution is a secure distributed data management system, in which each remote device stores its own local data in an internal encrypted database. The data from each device can be configured to flow up to a higher storage capacity device installed in a substation, operations centre, or other major node within the grid.
As the technology is based on NI CompactRIO embedded controllers, it is natural to use NI LabVIEW software for most of the embedded development to be deployed on VxWorks and Linux-based operating systems. Further, many grid operators run Windows, so there is a need for a cross-platform, highly flexible database solution that also supports encryption.
For this, an embedded database with a native LabVIEW API–Raima Database API for LabVIEW, implemented with RDM Embedded 12, is used. This provides a database management solution, specifically designed for applications deployed on NI CompactRIO and NI Single-Board RIO devices.
Stand-alone operation is therefore possible because the database resides in the LabVIEW data directory. It offers extended functionality to share data between multiple targets – whether sharing information between NI CompactRIO devices or outside computers.
The Raima Database API for LabVIEW provides programmers with a way to quickly and easily design data management functionality into their software applications, using an intuitive and easy-to-use programming interface that is familiar to them.
Rugged and reliable, with fast, high performance, Raima Database API for LabVIEW is available on the LabVIEW Tools Network and is the first database to deliver relational data management locally, on real-time NI CompactRIO devices. One or more NI CompactRIO or NI Single-Board RIO devices may store and share data without requiring connectivity to external database servers. Events may be logged and queried, streams may be captured and configurations may be shared through Raima functions.
The database technology supports VxWorks and support for the NI Linux Real-Time targeted platforms is now available, which was important for LocalGrid. Furthermore, its small footprint means it can run on a variety of embedded systems in field devices that may have very limited resources.
“RDM Embedded is fast, flexible, and designed for embedded targets allowing us to base our entire system around a single database product with native support for LabVIEW,” comments Beauregard. “This will simplify our design and reduce errors or unknowns during development.”
Development of this platform is moving forward quickly including multiple field trials. The Raima embedded database has been one of the keys to the progress of this development project.
Raima is a provider of high performance, always on database management system technology for both in-memory database usage and persistent storage devices. It delivers database solutions which are cross-platform, small footprint database systems designed for distributed architecture in resource-constrained environments.
LocalGrid provides a next-generation approach to solving one of the biggest challenges of our time – increasing the reliability of electrical grids to meet the growing needs of the 21st century. It is transforming power delivery through smart, flexible solutions designed to evolve in sync with the way we produce and consume energy – today and in the future. National Instruments equips engineers and scientists with tools that accelerate productivity, innovation, and discovery to meet not only grand but also daily engineering challenges in an increasingly complex world.
Steinar Sande is CEO of database technology specialist company, Raima Inc. of Seattle, USA.