It is a certainty that we willhave a deeply distributed power supply infrastructure and a densely built outsuper conducting power grid with loads also operating with similar technologyto truly minimize loss.
The weak point in this rapidlyemerging rosy power picture is the necessary transformer part of the equationwhich has always been a serious drag. Here we get a taste of the changes beginning to emerge although theyappear to still be tentative. They areworking out protocols as the customers line up.
I suspect we will see a new superconducting entrant shortly out of the Far East . It is to obvious and so necessary.
The Networked Grid: Can Solid-State Transformers Shape the Future ofthe Grid?
Advances in higher-voltage power electronics could usher in a newdistribution grid architecture, underpinning the future smart grid.
One of the panels that I will be moderating this afternoon, on day oneof Greentech Media's Networked Grid conference, focuses on the emergence ofsolid-state transformers. Though countless challenges exist, the advent ofthese new systems has the potential to be the most interesting story in thesmart grid over the coming decade. The concept of solid-state transformers isnot new (EPRI and traditional transformer vendors such as ABB, GE, Siemens andothers have been researching this for years), but as with many otherbreakthrough technologies, timing may be everything. The industry seems to bewitnessing a perfect storm of events that could finally take solid-state transformersfrom the R&D lab to live distribution grid circuit deployments in the nextthree to five years. What simultaneous industry events are occurring to helpmake this a reality?
1. The sheer availability and volume-based cost reduction of capablesilicon carbide semiconductor components (MOSFETs and IGBTs). As an example,Cree (which is represented on today's panel) is currently working on bringing anumber of these devices to market.
2. The shift from centralized to distributed power generation, and inthis case, primarily the proliferation of distributed PV. When select circuitsin the distribution grid reach 20% to 25%+ PV penetration, the potential forgrid instability, the ability to effectively manage voltage regulation, etc.,become real issues. I met with one major IOU recently that is capping the PVpenetration on any given circuit at 15%, given these concerns. This is at oddswith meeting RPS requirements, enabling renewables to scale, and the industryis actively looking for solutions, of which solid-state transformers may be oneof several.
3. Power layer grid infrastructure and assets are largely monolithicand unmanageable. With these devices representing the true core of thenetworked grid, this makes little sense going forward, especially as nearlyevery other surrounding smart grid technology is taking advantage of embeddedintelligence, network connectivity and remote manageability.
4. To a lesser extent today, but still a potential issue in the nextthree to five years and beyond is the growth of EVs and their associated loadprofiles. In some cases, the load of an EV can equal that of an entire homeconnected to a distribution transformer. I think you can see where this isgoing. Some IOUs are actually already doubling legacy transformer capacity inpockets of dense EV deployment. Though this is a viable band-aid solution rightnow, is it really the smartest approach going forward?
The promise for this new class of grid assets is immense, though so isthe number of challenges that must be addressed in bringing them to market.Skeptics will ask many relevant questions. Can these devices be designed andmanufactured to be cost-competitive with today's legacy transformers? Can asystem based on solid-state electronics, presumably with a complex softwarecontrol architecture, meet the efficiency and reliability metrics of existing,downright simple distribution transformers made largely with copper, iron andwell-understood packaging techniques? These are certainly very fair questions,but as the industry starts to dig deeper into the functions performed bysolid-state transformers, it will find that comparing them, metric-for-metric,with legacy transformers is ultimately comparing apples to oranges.
The industry needs to start thinking about these devices in an entirelydifferent way, and that is not going to happen overnight. This is nottransformer 2.0; it's an entire new class of grid asset that needs to beintroduced to the market and positioned as such. It's going to take time and marketeducation, as with any potentially disruptive technology.
Too often, when people first think about solid-state transformers, theinitial benefit that comes to mind centers around footprint (size and weight).It's true that these new devices can reduce footprint by an order of magnitude,significantly helping with inventory management and operations costs (inmany cases the installation cost of a distribution transformer is 10x thecapital cost), but this is only the tip of the iceberg.
With the advent of solid-state transformers, voltage transformation(the primary function of a transformer to step up/down voltage) becomes onlyone of many new features. When you start to consider many of the otherpotential features surrounding voltage regulation (CVR, programmable outputvoltage, OV protection for PV-centric circuits, etc.), power quality (reactivepower compensation and harmonic filtering), management and telemetry(integrated remote management, real-time load management, active line analysis,etc.), and other functions (such as the option for integrated storage), itbecomes evident that these new integrated devices are much more thanyesterday's transformers.
As you can see, comparing the capital cost of a legacy transformer withthat of a solid-state transformer, with many more integrated features andembedded intelligence, becomes an uneducated comparison. Nobody that is seriousabout solid-state transformers is claiming they can be introduced to the marketat the same price point of a traditional transformer, and the industry needs tostart understanding why this is the case given the additional benefits (andassociated systemic-level cost reductions) that can be realized. Beyond costand features, true innovators in this market are also meeting efficiency andreliability metrics, that naysayers may be skeptical of, defined by the DOE.
Lastly, another important point to understand is that proponents ofsolid-state transformers are not suggesting a rip-and-replace strategy forexisting transformers. The strategy for the introduction of solid-statetransformers will center around strategic benefits related to the 'greencircuit' of the future, rolling out devices on feeders with high PV penetrationand EV load. In addition, most utilities have a relatively well-known annualreplacement strategy (often in the 2% to 4% range) for aging transformers,failures, etc., providing another opportunity to introduce smarter devices,enabling a beneficial network effect as more devices are rolled out over time. Theidea is to get the initial devices in place where pain points exist and thenbuild a more intelligent platform over time. Also, international markets mayprovide significant greenfield
Despite advances in AMI and other early smart grid deployments, it'sbecoming clear that we are in the very early stages of a truly intelligentgrid. Until the embedded intelligence of these higher-layer control planearchitectures is integrated into grid assets sitting in the power plane, thegrid is only partially intelligent. Although there are enhanced sensorsand monitoring technologies being introduced into the power layer of the smartgrid, it's only the beginning, as true real-time decision making and actuation iswhat will ultimately be required. Solid-state transformers, and the manyadditional features and benefits they bring, have the potential to be acornerstone device for such functionality.
Attendees at The Networked Grid are looking forward to learning a lotmore about this topic in today's panel, titled Distribution Grid 2.0: The Dawnof Solid State
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