Intelligent Grid risks

An Executive Interview with Sensus Metering Systems

“The communications network requires the same reliability level as that expected in generations plants”
-Britton Sanderford

P&E. What do you see as the primary risks involved in intelligent grid adoption?
Britton Sanderford. Utilities in the United States are rushing to adopt smart grid initiatives to solve the issues of generation capacity, uninterrupted supply, carbon footprint and aging infrastructure. They will likely adopt solutions sooner rather than later. But as with all change there is risk. The key risks to avoid in intelligent grid adoption are security breech, infrastructure obsolescence and communications reliability issues.

P&E. What specifically do you mean by communications reliability?
HBS. If the smart grid is going to allow us to extend the usefulness of the current electric generation and distribution infrastructure the communications network requires the same reliability level as that expected in generation plants. Reliability goes hand in hand with the requirements for fast response time. This means that the communications paths themselves must have inherent automatic redundancy. This redundancy must be able to act within generation level time requirements in order to achieve the communication goals of the grid. Fast, redundant communications cannot be burdened with extensive rerouting algorithms which require time to determine a new or alternative path to the desired endpoint. The FlexNet, single tier communications network, for instance, insures that the communications latency has a predictable delay versus mesh systems which inherently have variable delays proportional to the number of hops required and the amount of interference sustained.

P&E. What are the answers to mitigating risks to the smart grid?
HBS. The first and most important point is sustainability, by that I mean protection of the utility infrastructure investment through network viability that insures usefulness through future changing and improving technology. At Sensus we refer to the philosophy of continual improvement. Every FlexNet endpoint is equipped with the ability to accept downloadable revised code. This capability is also inherent in the data collectors in the communications network which are called TGBs (tower gateway base stations). In addition to metrology and communications processors being downloadable the actual communications core is software defined. This means that modulations, protocols, frequency of operation, even data rate are defined in digital signal processing firmware and that means that the endpoints can be fully upgradeable as future requirements and features are developed.

Communications risks are mitigated by redundancy and speed of response time. Sensus FlexNet uses APA™ (All Paths Always) technology; this ultimate form of self-healing that ensures critical messages are delivered without re-routing delay. This means that every tower and every meter listens for every transmission on every frequency in parallel and all paths are used at all times simultaneously. A mesh system uses a different philosophy of serial communications and serial path recovery. This serial approach takes time in order to ‘heal a wound’ and find an alternative viable path. This healing time potentially delays time-critical messages when time-to-cure matters the most.

To avoid a security breech Sensus recommends a layered security method. First the spectrum that we operate on is exclusively available to the utility and does not compete with other users. Sensus does not offer a development kit to the public nor does it publish the core communications protocols and modulations. Each TGB is outfitted with both a primary and a secondary means of communications. Sensus recommends that one be a physical connection such as a wire or a fiber and the other be a wireless method including if appropriate satellite backhaul communications.

All of the risks facing intelligent grid early adopters can be lessened through awareness and planning. The time to act is now and the technology solutions are available in the market today.

Britton Sanderford was appointed to the position of Chief Technology Officer in July of 2006 when Sensus Metering Systems Inc. purchased the assets of Advanced Meter Data Systems LLC, (AMDS), which he had founded. Sanderford has published articles on multiprocessing computing, RF, protocols, modulations, telemetry and applications related to Smart Grid. He holds over 80 patents, pending and granted.