Building a truly interoperable “plug and play” eco-system of vendors and products is not a trivial task, especially in the electric utility industry. The California Public Utility Commission, in cooperation with the California IOUs (PG&E, SCE and SDG&E) and the vendor community have made great strides in creating such an interoperable eco-system for smart inverter management. The key steps in the process (and indeed to create any interoperable smart grid eco-system) have been:
All these steps have been necessary, even critical, to achieving the ultimate goal of a “plug and play” DER infrastructure. But are they sufficient? The answer is a resounding “NO” for a number of reasons. First, the CSIP certification, while necessary, by design covers only a small percent of all the conformance tests that could be run in the certification program. The intent is to capture the optimal set of messaging interchanges that account for 80-90% of the probable real interactions. While possible, it has not been practical in terms of cost/benefit to design and run tests covering all the possible messages and message combinations. Second, the CSIP conformance test is between a simulated test Client or Server and the device being certified, not between two or more commercial devices. That means it is not unlikely that small differences in the code that is not tested during certification of two commercial devices will result in infrequent but potentially expensive interoperability issues when communicating between them.
Thirdly, the certification test is only a snapshot at a point in time and software systems like these are undergoing constant updates to fix bugs and add new features. That means they might drift from full CSIP compliance over time.
In practice, the issues identified above are solved by deployments of many products from many vendors and finding the interoperability issues is the field. The conformance certification vastly reduces these kinds of issues but does not eliminate them. They are discovered and fixed in the real world of “hardware on the ground.” However, as the technology world has learned over the years, the interoperability issues of emerging technologies like smart inverter standardized communications can be further reduced through formal interoperability test events. In these events, vendors bring their products in released or even pre-released form and try different communications scenarios aimed at testing the kinds of messaging that is not conducted in the conformance test process.
But industry Interop events, while extremely valuable, are expensive and infrequent. For instance, the IEC 61850 community is only able to put together such events about every two years.
The SunSpec Alliance has just introduced the concept of an online, virtual Interop process they call “Non-Stop InteropTM”(NSI) which they have even trademarked. The NSI was announced in December at their annual Members Meeting (online virtual in December of course) and is in development with an operational goal during 2021. This is something that SunSpec has actually been thinking about for some time and in the age of Covid makes absolute sense. But it also makes sense in the age of ubiquitous digital communications and accelerated evolution of products. The idea is pretty simple and is enabled by the fact that communications interoperability testing can be conducted so that there is no need to have hardware even in the process – we’re talking bits over the air or wires from one logical product to another. One end of the Interop can certainly be a physical system but the testing is focused on the ability to successfully exchange information and messages between it and another system over an http or https transport. The two ends of the interop can be anywhere in the world as long as they have internet connections.
What SunSpec is doing is providing the middleware that not only enables the Interop sessions but provides additional capture and analysis of the traffic to insure that it conforms to CSIP and IEEE 2030.5 requirements. That additional analysis helps vendors determine if they are still conformant (at least on the messages used in the Interop) and provides the insights needed to troubleshoot interoperability issues so they can be addressed by the vendors. Further, capturing the Interop issues will enable the CSIP and IEEE 2030.5 communities to identify improvements in both the standard and the test specifications. And the infrastructure can be applied to other IEEE 2030.5 implementation profiles – e.g., for EV, DR, metering or other applications – once the test specifications and tools are developed around those profiles.
We have not seen anything like this in any smart grid domain. The Non-Stop Interop program promises to accelerate the interoperability of IEEE 2030.5 communications for smart grid applications and we think it is real contribution to the task of de-carbonizing the energy grid.
At this point, the only detailed information on the SunSpec Non-Stop Interop program is in the slides presented to members. For further information, contact Tom Tansy at email@example.com.