March 8 2011 Powerline Communications for Enabling Smart Grid Applications Prof Brian L Evans Wireless Networking and Communications Group The University of Texas at Austin Task ID 1836063 ID: 252680
Download Presentation The PPT/PDF document "SRC GRC Annual Review" is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
Slide1
SRC GRC Annual ReviewMarch 8, 2011
Powerline Communicationsfor Enabling Smart Grid Applications
Prof. Brian L. Evans
Wireless Networking and Communications Group
The University of Texas at AustinSlide2
Task ID 1836.0632
Task Description:Increase powerline communication (PLC) data rate for better monitoring/control applications for residential and commercial energy usesAnticipated Results: Adaptive methods and real-time prototypes to increase bit-rates in PLC networksPrimary Investigator:
Prof. Brian L. Evans, The University of Texas at Austin
Current Students
Current Status
Ms. Jing Lin Ph. D (expected graduation in May 2014)
Mr. Yousof Mortazavi Ph. D (expected graduation in Dec. 2013)
Mr. Marcel Nassar Ph. D (expected graduation in May 2012)
Industrial Liaisons:
Dr.
Anand Dabak
(Texas Instruments), Mr. Leo Dehner (Freescale),
Mr. Michael Dow (Freescale) and Mr. Frank Liu (IBM)
Starting Date:
August 2010Slide3
Task Deliverables3
Data and algorithms for receiver synchronization, channel measurements and modeling, and asynchronous impulsive noise mitigation (12/2010)Single-transmitter single-receiver (1x1) powerline communication system testbed: software package and documentation (5/2011)Data and algorithms for multichannel transmission for a three-transmitter single-receiver (3x1) powerline communication system (12/2011)Three-transmitter single-receiver (3x1) powerline communication system testbed: software package and documentation (5/2012)
Data and algorithms for crosstalk cancellation and low-power medium access control scheduling algorithms (12/2012)
Three-transmitter three-receiver (3x3) powerline communication system testbed: software package and documentation (5/2013)Slide4
Executive SummaryAccomplishments
Investigated PLC standardsLiterature survey on powerline channel/noise characterizationBuilt software and hardware framework for the PLC testbedSimulated receiver frame synchronization using chirp signal
Current work
Asynchronous impulsive noise mitigation algorithms
Future directions
Smart hand-shaking mechanisms between transmitter and receiver on the best sub-band (with high SNR) for transmission
Algorithms for synchronous impulsive noise mitigation
Noise and channel modeling and analysis
4Slide5
Background: Smart Grid Big Picture
Smart car : charge of electrical vehicles while panels are producing
Long distance communication
: access to isolated houses
Real-Time
: Customers profiling enabling good predictions in demand = no need to use an additional power plant
Any disturbance due to a storm : action can be taken immediately based on
real-time information
Smart building
: significant cost reduction on energy bill through remote monitoring
Demand-side management
: boilers are activated during the night when electricity is available
Micro- production
: better knowledge of energy produced to balance the network
Security features
Fire is detected : relay can be switched off rapidly
Source: ETSI
5Slide6
Background: Voltage Levels in Grid
Medium-Voltage
Low-Voltage
High-Voltage
Source: ERDF
6
“Last mile” PLC communications on low/medium voltage line
ConcentratorSlide7
Motivation for “Last Mile” PLC
Source: Powerline Intelligent Metering Evolution (PRIME) Alliance Draft v1.3E7
Concentrator controls medium to subscriber meters
Similar to wireless communications basestation
Applications
Automatic meter reading (right)
Smart energy management
Device-specific billing (plug-in hybrid)
Improving reliability and rate
Mitigate impulsive noise
Transmit over multiple phases
Standards target ~100 kbps
ERDF G3-PLC [Électricité Réseau Dist. France]
PoweRline Intelligent Metering Evolution
(PRIME) Alliance
7Slide8
PRIME Standard: Physical LayerOrthogonal Frequency Division Modulation (OFDM)
Divides transmission band into many narrow sub-channels
Transmission Band
42-89 kHz
Baseband sampling rate
250kHz
Subcarrier spacing
488.28125Hz
Number of subcarriers
256
FFT size
512 samples
Cyclic prefix length
48 samples
Number of data tones
84 (header) / 96 (payload)
Number of pilot tones
13 (header) / 1 (payload)
Subchannel constellation
Phase-shift keying (2, 4 or 8 levels)
Coding
convolutional coding (rate ½)
Max bit rate (uncoded)
42.9kbps, 85.7kbps, 128.6kbps
8Slide9
ChallengesPowerline Channel Impairments
Multipath and frequency-selective time-variant channel attenuationBackground noise, impulsive noise, and narrow-band interference
9
Source: Texas InstrumentsSlide10
Challenges (cont.)Performance degradation due to crosstalk
Induced by energy coupling across the phases or wires
Half-duplex operation eliminates ECHO and NEXT
Without FEXT cancellation, achievable data rate is significantly degraded
10Slide11
Presentation RoadmapFramework of PLC Testbed
Receiver frame synchronization using a chirp signalModeling of PLC channel noise11Slide12
PLC TestbedFramework of the 1X1 Bidirectional PLC Testbed
12
Hardware
Software
National Instruments (NI) embedded computers process streams of data.
National Instruments ADC/DAC generates/receives analog signals.
Texas Instruments analog front end enables half-duplex operation.
Transceiver algorithms implemented as C++
dynamically linked library, running in real-time embedded processors
Desktop PC running LabVIEW provides GUI for configuring and displaying key system parametersSlide13
Receiver Synchronization Using ChirpPRIME specifies a preamble to begin each burst.
Preamble is a linearly frequency modulated chirp over 42-89 kHzChirp has constant envelope (in contrast to an OFDM signal)Received signal
Correlated with chirp to find start of burst
Used to characterize channel
13Slide14
Experimental Results for SynchronizationTexas Instrument Development Kit for PLC
Two modems communicate with each other in interleaved mannerGather samples at 250 kS/s14
Rx
Rx
Tx
Tx
)Slide15
One Received Signal Burst
Preamble - - - - - - - Payload - - - -
Header 1
Header 2
2.048
-
each OFDM symbol is 2.240 ms
-
In time domain, a burst has the following structure.Slide16
Frame Synchronization by Correlation
[Bumille & rLampe]
Linear scale
Log scaleSlide17
Chirp in Freq. Domain for Channel Est.
FFT length is 512Slide18
Ex. Decoding Second Header Symbol18
Looking at positive subcarriers onlyBPSK modulated subcarriers (Information in phase)Slide19
PLC Channel NoiseThe powerline channel suffers from non AWGN noiseNoise as superposition of five noise types
[Zimmermann 2000]19
Source: Broadband Powerline Communications: Network DesignSlide20
PLC Channel NoiseThe powerline channel suffers from non AWGN noiseNoise as superposition of five noise types
[Zimmermann 2000]20
Colored Background Noise:
PSD decreases with frequency
Superposition of numerous noise sources with lower intensity
Time varying (order of minutes and hours)
Source: Broadband Powerline Communications: Network DesignSlide21
PLC Channel NoiseThe powerline channel suffers from non AWGN noiseNoise as superposition of five noise types
[Zimmermann 2000]21
Narrowband Noise:
Sinusoidal with modulated amplitudes
Affects several
subbands
Caused by medium and shortwave broadcast channels
Source: Broadband Powerline Communications: Network DesignSlide22
PLC Channel NoiseThe powerline channel suffers from non AWGN noiseNoise as superposition of five noise types
[Zimmermann 2000]22
Periodic Impulsive Noise Asynchronous to Main:
50-200kHz
Caused by switching power supplies
Approximated by
narrowbands
Source: Broadband Powerline Communications: Network DesignSlide23
PLC Channel NoiseThe powerline channel suffers from non AWGN noiseNoise as superposition of five noise types
[Zimmermann 2000]23
Periodic Impulsive Noise Synchronous to Main:
50-100Hz, Short duration impulses
PSD decreases with frequency
Caused by power convertors
Source: Broadband Powerline Communications: Network DesignSlide24
PLC Channel NoiseThe powerline channel suffers from non AWGN noiseNoise as superposition of five noise types
[Zimmermann 2000]24
Asynchronous Impulsive Noise
:
Caused by switching transients
Arbitrary
interarrivals
with micro-millisecond durations
50dB above background noise
Source: Broadband Powerline Communications: Network DesignSlide25
PLC Channel NoiseThe powerline channel suffers from non AWGN noiseNoise as superposition of five noise types
[Zimmermann 2000]25
Source: Broadband Powerline Communications: Network Design
Can be lumped together as Generalized Background NoiseSlide26
Generalized Background Noise26
Source: Broadband Powerline Communications: Network Design
Power spectral density of generalized background noise
Slide27
Impulsive NoiseAsynchronous noise dominates this class of noise
27Source: Broadband Powerline Communications: Network Design
Need to statistically model two aspects:
Impulse amplitude distribution
Inter-arrival time between impulsesSlide28
Asynchronous Impulsive Noise ModelingAmplitude statisticsClass-A Middleton
[Umehara]Weibull Distribution [Umehara]Empirical Fits [Zimmermann]
Interarrival statistics
Exponential distribution
[Zimmermann]
Empirical Fits
[Zimmermann]
Partitioned Markov chains
[Zimmermann]
28
Source: Zimmermann
Source: ZimmermannSlide29
Preliminary Noise Measurement29Slide30
Preliminary Noise Measurement30
Colored Background
NoiseSlide31
Preliminary Noise Measurement31
Colored Background
Noise
Narrowband NoiseSlide32
Preliminary Noise Measurement32
Colored Background
Noise
Narrowband Noise
Periodic and
Asynchronous Noise Slide33
List of Acronyms/Abbreviations
Acronym/Abbreviation
Meaning
Cyc. Pref.
Cyclic Prefix
FEC
Forward Error Correction
FEXT
Far-end crosstalk
LV/MV
Low-voltage / medium-voltage
MAC
Medium Access Control
MIMO
Multi-Input Multi-Output
NEXT
Near-end crosstalk
OFDM
Orthogonal Frequency Division Multiplexing
PAPR
Peak to average power ratio
PHY
Physical layer
PSD
Power Spectral Density
SFSK
Spread Frequency Shift Keying
33Slide34
ReferencesBumiller and Lampe, “Fast Burst Synchronization for PLC Systems,”
Proc. IEEE Int. Sym. Power Line Comm. and its Applications, 2007, pp. 65 - 70H. Hrasnica, A. Haidine, and R. Lehnert, Broadband Powerline Communications: Network Design, Wiley 2004.
A. G. Olson, A. Chopra, Y. Mortazavi, I. C. Wong, and B. L. Evans, “Real-Time MIMO Discrete Multitone Transceiver Testbed”,
Proc. Asilomar Conf. on Signals, Systems, and Computers,
Nov. 4-7, 2007, Pacific Grove, CA.
D. Umehara, S. Hirata, S. Denno, and Y. Morihiro, “Modeling of impulse noise for indoor broadband power line communications”,
Proc. IEEE Int. Sym. on Information Theory and Its Applications
, Oct. 29-Nov. 1, 2006, pp. 195-200.
M. Zimmermann and K. Dostert, "Analysis and modeling of impulsive noise in broad-band powerline communications,”
IEEE Trans. on Electromagnetic Compatibility
, vol.44, no.1, pp.249-258, Feb 2002.
Freescale solutions for smart metering and smart grid enablement,
http://www.freescale.com/webapp/sps/site/overview.jsp?nodeId=02430Z6A10
Texas Instruments Powerline Communications solutions
http://www.ti.com/ww/en/apps/power_line_communications/index.html?DCMP=plc&HQS=Other+OT+plc
34