Monthly Archives: March 2014

Smart Sensors for the SG: You Can’t Manage What You Don’t Measure

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Dom Geraghty

 

An Integrated Measurement Strategy for the SG

Obviously, since the SG is inanimate, we don’t expect it to intuit how to do “smart” things by itself (!). We have to provide it with data, and with analytical rules. Even the recent introductions of AI-based algorithms in some SG applications must still be derived from “learnings” from empirical data.

At present, the deployment of SG applications can be characterized as “tactical”-- uncoordinated with other activities in the SG, and special-purpose in nature – certainly not following the holistic, long-term visions of SG architectures and power markets developed by such entities as GWAC, NIST, EPRI, IEC, IEEE, SGIP, etc.  The result is a hodge-podge of application-specific sensors with different capabilities which don’t communicate across applications and which operate in different time domains. But it does not need to be like that, as we shall outline below.

Let’s Define Measurement, Sensors, and Smart Sensors

10. DSC_1334-150x150Smart sensors are the fundamental building blocks for the implementation of a truly “smart” grid. They are an essential part of every SG solution. Regular analog sensors become the “smart sensors” of the SG when they add intelligence to the measurement function, i.e., analog to digital conversion, processing power, firmware, communications, and even actuation capability.

We can think of smart sensors as the first link in a four-link SG decision-making chain that consists of:

(1) Location-specific measurement -- sensor function only

(2) Monitoring -- a sensor with one-way communications functionality

(3) Diagnosis at the “edge” -- a sensor with localized diagnostic intelligence based on data analytics and/or centralized diagnosis based on communicated sensor data

(4) Edge-embedded control actions (based on embedded algorithms, including Remedial Action Schemes (RAS)) -- a sensor with intelligence and control/actuator capability. The algorithms for this functionality could also be centralized and use two-way communications with an “edge” sensor/actuator, and/or they could drive peer-to-peer coordination of control actions at the “edge”; however, a substantial amount of R&D still needs to be done to develop autonomous real-time or quasi-real-time control algorithms for power distribution systems

To Date, Smart Sensor-Based Measurement in the SG Has Been “Tactical”

Granted, as we’ve said before, there is a reason for this tactical approach to sensor deployment – up to now the choices of SG projects are driven by energy and regulatory policies and rules that target a limited set of SG applications. Fair enough -- none of us expect that the evolution of the SG will follow a “grand deployment plan” – it will be imperfect, following the zigs and zags of these real-world drivers.

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