The rising volume of DERs on the electric grid jeopardizes every legacy power engineering paradigm in place. These devices create backfeeds and voltage challenges, as well as hidden load, balancing and inertia issues. As such, grid operators cannot afford to ignore these devices. Even at low penetration levels, utilities need to build their situational awareness of where DERs are located, what kind of asset they are, and what their current status is, in addition to associated consumption levels or storage availability. Operators need to be able to closely monitor DERs, as well as control them, especially when traditional grid levers are not sufficient for optimal network operations.
In addition, most DERs do not belong to electric grid operators, they belong to the prosumer, and are being marketed as part of innovative service offerings – housing, transportation, etc. Therefore, DERs are usually attached to an interconnection or aggregation contract which states the limits to their use by the prosumer and the aggregator or the grid operator (e.g., max number of times the DER can be dispatched per day/week/month, max ramp-up time, minimum advanced notice period before a dispatch, etc.). When controlling DERs, the utility needs full awareness of all contractual frameworks and operational constraints already in place.
One may think that SCADA communications will suffice, being the traditional method to connect with any breaker, transformer, or other devices on the grid. But for many utilities the number of small and disperse DERs on their network are now adding up to tens or hundreds of thousands, and are expected to continue to grow into the millions. Unfortunately it isn’t economical to connect each and every DER with a SCADA protocol. For small DERs, SCADA communications and dedicated Remote Terminal Unit (RTU) hardware are prohibitively expensive. A residential DER owner will never be equipped with the same type of communications as an electrical substation. What a residential DER owner has available is the Internet. With that in mind, what operators need is a communication protocol that runs on the Internet.