The smart grid requires exchanging data between different devices from many manufacturers in the field. Traditional utility technologies are very often vendor silos utilizing proprietary hardware, telecommunications and software platforms that communicate to a centralized hub. Last year at Distributech 2014 a group of Duke Energy and six companies called the “Coalition of the Willing” (COW) – Accenture, Alstom Grid, Ambient Corporation, Echelon, S&C, and Verizon, demonstrated interoperability between their products. The goal was to demonstrate that data and control commands can be shared across multiple vendor platforms (typically proprietary) to achieve interoperability with lower costs and faster response times.
At Distributech 2014 Duke energy also described the challenges Duke has encountered in cleaning, merging and managing operational data, combining it with other types of data including social media, and developing analytical tools to extract meaningful information. Duke also described an innovative approach for involving vendors in the development of their smart grid platform and applications, which provided the basis for vendor involvement in COW.
COW 1 Volt/Var Optimization
The first phase of this project was to convert a Volt/Var Optimization (VVO) function to run on a distributed platform. It used a “communications node” and a standards-based messaging architecture to enable peer-to-peer communications to integrate data from different vendors' systems. Each of the COW participants exposed some data via a standards-based interface (Field Message Bus). The application read two residential meter voltages supplied by Echelon meters and brought the data back via Power Line Carrier (PLC) to the Ambient communication node. If an under voltage condition was detected, the application sent a close command to the control via DNP3 through peer to peer messaging over the Verizon Wireless network. The capacitor control closed the capacitor bank to alleviate the under voltage condition on the meters. Finally, the Alstom DMS was updated with the new state of the capacitor.
Open standards, open source
The COW 1 project involved open source hardware (Raspberry Pi), open source software and open standards. According to Duke the Field Message Bus (FMB) is intended to be an open standard-based, common logical publish/ subscribe (pub/sub) interface that connects multiple disparate grid devices, telecom networks, and information systems. It is the key technology enabler to demonstrate the benefits of the distributed architecture by facilitating interoperability between multiple different vendor’s OT, IT, and telecom systems. It uses open-source software to translate data to a common publish and subscribe messaging interface using the IEC Common Information Model (CIM) data model. Other open standards that are being used in this project include industry-standard protocols as DNP3 and Modbus and messaging protocols like MQTT (for lightweight applications) and AMQP (for heavy duty messaging).
COW 2 Islandable microgrid
Last June Duke Energy announced the next phase of their interoperability project with an expanded groups of vendor partners. The second phase will include the operation of a microgrid system which will integrate distributed renewable resources such as solar PV and battery storage with a field message bus-based distributed intelligence platform with wireless communications to devices.
The new project will support another open standard. The Object Management Group's (OMG) Data Distribution Service (DDS) for Real-time Systems provides a secure publish-subscribe messaging protocol. Many real-time applications involve publishing “data” which is then available to remote applications that are interested in it. In a utility setting this communications model needs to scale to thousands of publishers and subscribers in a robust manner.
A data model based on the CIM standard will be implemented into an open field message bus to support standardized object model representations. The use case for this demonstration project will be an islandable microgrid which Duke will implement and operate at its smart grid test facility.
Duke Energy has defined a Distributed Intelligence Platform (DIP) Reference Architecture for this project. According to Duke, the reference architecture is intended to document Duke Energy’s technology roadmap for interoperability using open standards-based distributed information systems.