1. Achieving High-Resolution Situational Awareness in Ultra-Wide-Area Cyber-Physical Systems
PIs: Hairong Qi, Qing Cao, Yilu Liu, and Leon Tolbert
Students: Brandon Johnson, Liu Liu, Wei Wang, Sisi Xiong, Yanjun Yao, and Lingwei Zhan
Electrical Engineering and Computer Science
University of Tennessee, Knoxville
NSF CPS PI Meeting, October 2013

2. Rationale
Develop a high-resolution, ultra-wide-area situational awareness system
Employ the power grid as a target application
Synergistically integrate
Sensing: High-resolution sensing with innovative design of frequency disturbance recorder at the distribution level
Processing: High-resolution online data analysis through event unmixing
Actuation: Coordinated local
actuation with load as resource
Online implementation:
Novel programming abstractions
such as DataSQL
DATA
PROCESSING
ACTUATION
SENSING
Physical
World /System
ONLINE
IMPLEMENTATION
To turn a large volume of real-time “mixture” data into actionable information and help prevent outages from happening

3. Sensing Towards the Edge
Innovation:
Accurate frequency measurement from low voltage distribution systems
Wide deployment of Frequency Disturbance Recorders (FDRs): measure essential transmission level information at the distribution level using low-cost sensors.
New wireless non-contact versions are being developed
Challenge: Noisy voltage signal at the distribution level
Comparison to state-of-the-art: PMU
Transmission level
Expensive
Thus far there are about 150 FDRs installed and another 40 installed worldwide. Currently, the system is operated by the University of Tennessee and Oak Ridge National Laboratory as a joint effort.
The price difference between PMU and FDR plus installation is $80,000 vs. $1,000

4. Data Analysis through Event Unmixing
Innovation
A new conceptual framework, event unmixing:
Go beyond what are immediately detectable in a system, providing high-resolution data understanding at a finer scale.
Challenge
The universal existence of “mixture” or “mixed measurements”
How to construct a dictionary to reflect event dynamics
Comparison to state-of-the-art: single event detection
Nonnegative Sparse Event Unmixing (NSEU): Multiple event detection, recognition and temporal localization in ONE unmixing process at each FDR location
Generator Trip Accuracy: 98%, FA: 0%; Line Trip Accuracy: 82%, FA: 0%

5. Actuation with Load Participation
Innovation
Load participation by residential or small commercial
Challenge
How much we know about loads?
How to participate?
A residential power demand simulation tool
Markov chain-based occupant behavior models
Dynamic models of all major residential loads
Models for residential demand response
Residential power demand decreased by 600 kW (~30 %) for 9.5 minutes.
Residential power demand increased by 350 kW (~18 %) for 18 minutes.
Most load shedding is for large industrial plants.  Load participation by residential or small commercial is relatively new.  
To understand the impact residential loads have on the power system, we developed the Residential Power Demand Simulation Tool (the tool’s GUI is shown on the right). This tool was developed in MATLAB and combines Markov chain-based occupant behavior models, dynamic models of all of the major residential loads, and models for residential demand response. It can be used to understand the potential resources that can be provided by residential loads. This tool simulates real and reactive power demand on a 1-second time scale.
Simulation of 1000 homes on Sunday June 3rd, 2012 (At 4 pm, shed 50 % of HVACs).

6. Online Programming by Approximation
Innovation
Novel and compact data structures that are probabilistic by nature for data programming abstractions in DataSQL on resource constrained platforms
Challenge
Accurate data measurement and storage vs. approximate identification and measurement
Key-value bloom filter – supports the approximate key-value storage service 6%
0.12%
4.5M
p=0.1%, 0.01%, 0.001%, %
FP FN Memory

7. Our Team Hairong Qi Leon Tolbert Yilu Liu Charles Q. Cao DATA
PROCESSING
SENSING
ACTUATION
Physical
World /System
ONLINE
IMPLEMENTATION
Leon Tolbert
Yilu Liu
Charles Q. Cao

8. Target Market
Monitor devices and Load control devices with online processing algorithms
Huge economic impact
FNET/GridEye (joint effort by Univ. of Tennessee and Oak Ridge National Laboratory)
150 FDRs installed in US and Canada
Another 40 installed worldwide
From the utility perspective:
1. If the utility can get enough load participation so that peak demand can be considerably reduced, then
a. The utility can avoid having to purchase power from a neighboring utility which is usually at very high prices.
b. The utility may avoid having to build as many "peaking units" generally natural gas turbines.  Again, cost savings in terms of deferred construction, maintenance, and operation costs.
From the customer perspective:
1. If they agree to have interruptible load, generally can purchase power at cheaper prices.
2. If utilities start using real-time pricing, customers can avoid using large amounts of power during high price times and save money.
So methods and devices that allow greater load participation has both customers and utilities as markets.