Typical North American power grids developed 50 to 75 years ago use a centralized design. However, factors such as population growth, urban sprawl, and renewable power generation are driving requirements for a decentralized architecture that enables more fault-tolerant and scalable distributed generation. With the rapid pace of technology deployment and urgent adoption of renewable, distributed energy sources to replace fossil fuels, the traditional power grid must change. According to LocalGrid Technologies, electricity distribution companies must embrace modernized grids that are intelligent, continually evolving electricity networks to deliver enhanced customer satisfaction, increased service reliability, and energy security while enabling adherence to new environmental standards.
National Instruments and Prolucid Technology Inc, a NI Alliance Partner, are leading the development of “smart” distributed power generation and MicroGrids. Changing to a decentralized approach to power management enables distributed generation by making renewable energy available that is either utility or state owned, or available through feed-in-tariff (FIT) programs. Toronto Hydro-Electric System Limited (Toronto Hydro) has been a participant in this project. Toronto Hydro is one of the largest municipal electricity distribution companies in Canada and has approximately 1,600 feeder lines and 719,000 customers, according to their website. Making the most effective use of multiple generation sources requires a dynamic and flexible distribution grid. This is a key driver for grid modernization. Toronto Hydro hopes to use intelligent monitoring and control to help overcome many restrictions, and the Intelligent Node Project with Prolucid is their first effort in this important area.
A flexible hardware and software platform with a highly modular nodal approach is required in the design of a distribution monitoring and control platform to ensure the scalability of the project. Prolucid therefore chose the cRIO-9068 module for the Prolucid Cell Controller to collect and process data from remote devices on the feeder network. The company also selected it for the Cell Asset Node to distribute energy resource integration, remote power quality monitoring, and dispatch command management. Prolucid used LabVIEW system design software to develop the Prolucid DataFabric, so industry experts and grid operators, who were previously unfamiliar with LabVIEW software, could read, understand, and even write application-specific algorithms deployed to the in-field devices.
The CompactRIO platform provided Prolucid an off-the-shelf, software-defined controller that delivered the I/O and processing flexibility needed to standardize on for the application. Ruggedness, flexibility, and the productive LabVIEW development environment, all featuring a competitive price-for-performance specification, made CompactRIO a clear choice compared to other controller options in the market.
The system architecture designed by Prolucid has several key benefits to MicroGrid and distributed grid applications. Utilities can recognize cost savings through deferred capital investment by generating more power behind existing transformers and moving more power through assets in off-peak hours. With data describing the grid behavior, utilities can make targeted asset investments based on high-resolution, more granular data to optimize growth management. With the availability of real-time data, analysis, and autonomous control actions, utilities can do more with existing assets to isolate and correct faults and improve grid stability.
Providing decentralized energy management oversight at the feeder level gives electrical utilities additional tools to cost-effectively manage peak load, increases grid efficiency, and improves asset use for both new and aged infrastructure.
Prolucid’s 21st Century Grid Network Architecture
|20th Century Grid
||21st Century Grid
|Built for centralized generation
||Accommodates distributed generation
|Manual power restoration
|Check equipment manually
||Monitor equipment remotely
|Limited control over power flows
||Pervasive control systems
|Few customer choices
||Many customer choices
Table 1. Comparison of Modern Grid Characteristics
The challenge in building a MicroGrid or distribution topology system is that each installation is unique. Installations vary by type and number of devices deployed, parameters, and operator objectives. Only with the right mix of off-the-shelf modular hardware and sophisticated modular software architecture can a system that is highly reusable with low deployment costs be developed to meet these varying requirements.
This MicroGrid project involves the following main components:
- The Prolucid Cell Controller (cRIO-9068), which is a substation controller for collecting and processing data from remote devices on the feeder network
- The Cell Asset Node (cRIO-9068), which is used for distributed energy resource (DER) integration, remote power quality monitoring, and dispatch command management
- Centralized management tools to monitor and configure the remote devices
- Integration between core operational systems and existing devices
Development Platform Considerations and the cRIO-9068
Prolucid started using the NI cRIO-9076 controller based on a VxWorks real-time OS; however, the application was also ported to the cRIO-9068, which immediately delivered several additional benefits, including increased processor performance, a larger FPGA, access to an open real-time OS ecosystem, and improved ruggedness.
Within 24 hours of receiving the first cRIO-9068, Prolucid engineers were able to port their LabVIEW application from the cRIO-9076 and see increased processor performance. In benchmarking, the 400 MHz single-core processor of the cRIO-9076 successfully ran the application at 70 percent CPU utilization. But engineers saw a 4X performance increase with the cRIO-9068 processor running the exact same LabVIEW code, which had a combined CPU utilization of 17 percent. Along with the improved processor performance, more processing algorithms were able to fit within a larger FPGA fabric.
In addition to performance enhancements, Prolucid leverages the Linux-based OS open ecosystem, which helps engineers run third-party applications such as a Mono (a C# compiler) more easily. The user and application security built into the OS also allows for more secure field deployment of the solution. With the cRIO-9068 extended temperature rating of -40 °C to 70 °C, deployment into the harsh field environments is also possible.
Prolucid DataFabric Application Software
Prolucid’s DataFabric is an easily scalable distributed monitoring and control system, including high-speed acquisition, logging, and control with data reduction from distributed nodes up to the operations network. A decentralized control design pushes the decision making to the remote devices, which improves fault tolerance and reduces the need for a highly reliable, high-bandwidth communication backbone. Custom calculations and analytics within the software can be designed from a centralized location and deployed remotely to the devices. Through the NI platform, Prolucid engineers also can take advantage of the extensive toolkits for power measurement, communication, and industry certifications for that platform. The application uses the DNP3 (Distributed Network Protocol) featured in the platform as well as the NI Electrical Power Suite to perform online analysis and calculation of power signals. These protocols are required, and, using the NI platform with toolkits that were already certified and tested to work, Prolucid reduced its costs and effort.
Communication and Messaging Architecture and Database
A vital component in the network architecture is the communication layer, which is critical to the scalability, efficiency, and reliability of the distributed network. Prolucid selected the data distribution services (DDS) protocol, using the Connext DDS toolkit from Real-Time Innovations (RTI), because it is designed specifically for distributed communications networks with mission-critical, military applications and supports cross-platform compatibility, including Windows, Linux, and VxWorks. Additionally, the database that manages the incoming data, analytic results, and network configuration is based on the RDM Embedded database from Raima, a platform-agnostic database designed specifically for embedded applications. This allowed Prolucid to share data across platforms with the same data structure and same architecture, which was more efficient.
System Architecture Benefits
The system architecture enabled by CompactRIO has the following key benefits for MicroGrid and distributed grid applications:
- High efficiency, secure communication, and data aggregation that operate on low-bandwidth, intermittent, and high-speed links
- Ability to deploy software to low-memory, less powerful embedded targets as well as high-end systems to scale the number of connected devices and channels and custom algorithm processing
- Submillisecond data messaging performance and scalability with appropriate communications links
- Scalability from tens to thousands of devices with little additional overhead
- Deterministic performance from low latency and jitter
- Cross-platform and programming-language-agnostic design with APIs for many current CPU architectures and OSs as well as APIs for C, C++, C#, Java, LabVIEW, and web services
- Open architecture and standards-based specifications and technologies
Without the modular software and toolkit architecture based on LabVIEW and the CompactRIO platform, the Prolucid engineers could not build the modular, distributed, and flexible system needed for the modern MicroGrid at the price and performance required. Future grid infrastructure must be more flexible, scalable, and adaptable to subscribers’ needs. A static grid that does not change over 40 years will not suit the needs of our rapidly evolving society and technology. By using a more intelligent, modular, and adaptable generation source and architecture, we can more efficiently meet our power needs in both the developed and developing world.
Proclucid Technologies Inc