Carbon-Pros Analyst Blog

You can think of the smart grid as a similar to the Internet in that it is a loosely coupled system of systems. And like the Internet, a single, all- encompassing architecture is not practical. Instead the legacy grid provides the foundation on which we add several layers of communication networks and applications with many systems being connected in real time.

Smart grid architecture will develop as a composite of many system and subsystem architectures. This will allow for maximum flexibility during implementation and will simplify interfacing with other systems. It also supports evolution of smart grid as new applications and technologies become feasible.

To support the standards development process, the GridWise Architecture Council (GWAC) created an eight-layer model. The model illustrates the many levels of standards and technologies required to support end-to-end interoperability.

As you can see in the figure, end-to-end interoperability involves everything from the electrical connections at the bottom of the stack to the regulatory environment at the top. Levels 1-2 involve standard connections across the myriad of grid components and communication networks. Levels 3-4 insure that the meaning of data and information remains intact as it flows across different elements. Levels 5-6-7 deal with the business and organizational issues of interconnected systems. Level 8 points to the need for a regulatory environment that does not impede the interoperability of systems.

The GWAC Stack is a means to identify well-known interfaces. Unambiguous interfaces are essential to interoperability. This s demonstrated on the Internet which has a physical and data link layer that allows messages to cross any type of network (Ethernet, Wi-Fi, microwave, optical) and still be managed end-to-end by a common network layer. On the Internet, protocols such as TCP/IP handle the transport details making sure that data packets get to their destination correctly, while higher level protocols such as HTTP and XML structure the message so that it can be interpreted properly at each end of the network.

Source: GWAC Interoperability Context, March 2008
http://www.gridwiseac.org/pdfs/interopframework_v1_1.pdf