Power Line Communicationfrom Home Automation
toSolar Farm Monitoring
Ekachai LeelarasmeeChulalongkorn University, Bangkok
Thailand funded by Ratchadaphiseksomphot Endowment Fund
of Chulalongkorn University (RES560530056-EN)
Power Line Communication (PLC)• Since 1988 • Utilize existing AC power lines to carryhigh freq data signal
• Data rate from 1Kbps – 200Mbps
www.prime-alliance.org
230KVac
23KVac
220Vac
PLC signal on AC 220V
622V
80kHz
0.4V
PLC
PLMPLMPLM
Device Device
Voltage (Parallel) Mode PLC
Device
Device = Appliance, Computer, ADSL, etc
AC line
data
PLM = Power Line communication Module
PLM 80-90kHz
64Kbps, OFDM
10μF
100Ω
15nF 470μH
470nF
.6 8μH:10 1Tx
Rx
ac220VFilter
DataDSP
Type Narrow Band Broad Band
Freq. 3-500kHz 2-25MHz Data 2-128Kbps 10-200MbpsRange > km < 300m Uses Monitor/Control High Speed DataSTD PRIME,G3,X10 Home Plug AvApp Smart Grid Home Network
PLC classification
www.sentec.com
Home Automation (narrow band < 500kHz)
X10, LonTalk
Low speed <128kbpsControl &Monitor
www.aztech.com
internet
Home Area Network Broadband <25MHz
Home PlugHome Plug AV
High speed<200Mbps
www.smartlighting.com
Street Lighting
Lamp maintenance & dimming
Long range
EV Charging station
www.greenvity.com
Smart Grid
MDMOMDSMetc
Narrow band, Long range
PRIME, G3
Problems with PLC1) Noises
1.1) Motor & Switch (intermittent)1.2) Switching Power Supply
(Periodic impulse)
2) Unknown Topology2.1) Line characteristic varies 2.2) Frequency & Time dependent2.3) Multiple reflection (coupling loss)
Smart Grid Technologylow data rate (32kbps), real time, long range
PoweRline Intelligent Metering Evolution
Open International PLC Standardfor Advance Metering, Grid Controland Asset Monitoring applications
2,500,000 meters deployed worldwide
PRIME TreeTopology
BN: Base Node (DCU)SW: Switch Node (Meter)SN: Service Node (Meter)
Smart Meter
PLC (PRIME)
RF (Zigbee)
220V AC in 220V AC out
RF, Optic
Advance Metering Infrastructure (AMI)
CorporateUtility Network
DataConcentrature(BN)
PLC
SN SW
SW SN
SN
Internet
PRIME Protocol Layer
41.992KHz – 88.867KHz 128Kb/Sec OFDM
PRIME OFDM
PRIME MAC Frame Structure
Solar Farm Monitor
8MW 86668 PV panels: fixed topology
+ -20-100V50-200W
World Bank 2012 Renew energy projects
Global (MW) Thailand (MW)
Bio 1277 39
Hydro 31060 0
Wind 28900 127
Solar 7695 326
Blackout22 May 2013
Lightning strike on 500KV
Not enough localPower generation
Multi-String Topology
PV’s are not identical but must operate at the same current un-optimal
8 20 PVs− AC
8 20 PVs−
AC
AC
DC
DC
InverterI I
1P nP
Mismatched PV panelsdefect, cloud, trees, airplane, directioncrack, dust, leaves, aging, temperature
P1 + P2 < P1m + P2m 20% loss
P1 P2
I
P1m
P2m
weak
I
P1
P2
Effect of Mismatched PVs
I
Solar Farm (Health) Monitoring
MU
CUMUMU
MU
DCUDC
DC
AC
AC
Controlcenter
CUCU
CU
DCU
MU : Monitor Unit (V,I,Temp)CU : Communication UnitDCU: Data Concentrator Unit
RF 433MHz or 2.4GHz
Expensive, Fragile & Complicate
MUMU
MU MU
CU CU
CUCU
DCU
DCU
Controlcenter
DC
DC
AC
AC
Serial Mode PLC
MU
CUMUMU
MU
DCUDC
DC
AC
AC
CUCU
CU
DCU
AC Current Mode PLC (analog tech)
Low cost: uses current transformer for couplinghigh frequency current signal
MU MU
MU MU
CU
CU
CU
CU
DCU
DCU
DC
DC
AC
AC
ControlCenter
Pulse PLC (digital tech)
Low cost. Toggle switch to transmit data
MU
MUMU
MU CU
CU CU
CU DCU
DCUDC
DC
AC
AC
ControlCenter
MU MUTx Rx Rx
acI
Superimpose AC Current onto DC Current
1) AC Current Mode PLC
o
PV & INV must be short circuit at carrier frequency ω
TxiV
acI
Rx oVoIiI oZ =∞ iZ 0=
PLC Current Coupling Circuit
m kL ,L
iV oV2C
1C
1L
acI acI
Tx Mode
o1 m 2
1ω(L L )C
=
oZ to couple current=∞
2o
1 m k 2
1ω(L (L L ))C
=+
kL
iV2C 1L
acI acI
mL
Ideal
oZ
2C1L
acI acI
mL
Ideal
i 2 iI jωC V=
oZ
Rx Mode
ac 2o o i
o 1 11 1
jI C1ω ; V Vω C CL C−
= = =
iZ 0 to avoid loading DC line=
22 o k 2o 2
1 k 1 o 1 k 2
1 ω L C1ω(L L )C 1 ω (L L )C
−= •
+ −
mL
oV2C
1C
1L
acI acIIdeal
kL
iZmL
oV
2C
1C1L
acI acIIdeal
iZ
50W Amorphous PV panels
3Ω
250kHz
Carrier frequency
PVZ
oω0.81A 9802.2 0.8μ
pvZ
m
k
s
L
L 84μL 36μR 50R 10k
=
=
=
=
m kL ,L
iV oV2C
1C
1L
acI acI= =
= =
=
= =
=
1 1
2 s
L
i ac ac ac
L 220μH ; C 5.22nFC 1.39nF; R 50R 10K ; V 1V ; I 2.18mAEnergy loss per PV 14μW
Test Experiment for simulation
MU MUCU CU DCU
#1 #8
3Ω 3Ω
Monte Carlo Simulation 50 simulations, 20% over 3 sigmaGaussian Distribution
o
i
VV
Amplitude Shift Keying (ASK)
Data Rate = 25kbit/sec
40μS40μS40μS 40μS
1 0 1 1
4μS
250kHz
MU & CU Circuit
Consume 50uA (2.5mW) while idle
CU
MCUoD
iDADC
iV oV1MΩ
10kΩ
50V + −
3V REG
GND
Low Power MU & CU Circuit
M1 is on to wake up MCUMCU turns on/off M2 to keep power on/off
to save power
CUMCU
oD
iDADC
iV oV
50V + −
toADC
M1M2
3V
Gnd
M1 M1on on
Low Power Communication Protocol
CU DCUwake (111)addr & instrackresponsesleep
MUMU CUCU DCUDC
AC
Pulse PLC
A switch closes temporarily to create a pulse thatpropagates through the DC Power Line.
DV (n 1)V if one PV switch closesV 0 for all PV if DCU switch closes
= −
=Thus DCU can broadcast data to all PVs
PV can reply to DCU only
MU
#1 #n
VMU CUCU DCU
DC
ACV
DV
Ideal Waveforms: 8 x (50V) PV
DCUV
pvVPV DCU→
DCU PV→400V
300μ 600μ
0 01
8μ
50V
Pulse shaping due to PV Capacitor
pv
ph
C 65nFV 50V
I 0.015 0.5A
==
= →
r
r
T 6.5 220μSData Rate
1 <8μ T
4.4kpulse / s
= →
+
=
MU+
−
pv pvr
ph
C VT
I=
V
CloseV
pvCphI
PV
8μS
Open
DC Line
Close
AC
DCTransmission Line
μL 1.475 H / m, C 11.3pF / m= = DCUV+
−
Ringing due to transmission line effect
cause ringing
Ringing through DC Line
15m cable35m cable
1.8MHz
close
R 10; L= ; C=
Ringing Suppression at DCU
Y o
Y
R 410Ω to match ZC 2nF to block DC
=
=
oZ DCUV+
−
YR
YC
Ringing Suppression at the Switch
pvV
+ −pvV + −pvV
C R
Hard Switch
pvV
Soft Switch
50W Amorphous PV panels
DCUV
a) Hard Switch (IRFS630)b) Terminate DCU with 410 + 2.2nFc) Soft Switch with 1.5K & 150pFd) Soft Switch under weak sunlight
Negative edge detectorQ is OFF when idle (zero power)
ON when there is a neg. pulse
1C
2C
2R
1R
3VPVVDC line
PVpanel
μC/ON OFF
Switch
pT
Q
PT
in
out
1P PV
1
2∆ ;
C C∆C
=+
2
1 2P
R∆ ∆ 0.7R R
≈ ≤+
( )2 2 1P 2(R R )(C C )lnT ∆ / 0.7= + +
DesignEq.
1C
2C
2R
1R
pT
QΔPV
ΔP
Δ3
3V
3
3V
1 2 1 2 PV
PP
R R 10KΩ; C 470pF; C 4.7nF; ∆ 80V∆ 7.27V T 170μ; ∆ 3.6 S3V;
= = = = =
== =
Experimental Result
Strong Weak
Broadcast by DCU
One MUresponses
Edge Detector with Regulator
1C
2C
2R
1R
3V40VDC line
PVpanel
MCU
Q
Edge Detector with Regulator
1C
2C
2R
1R
3V40VDC line
PVpanel
MCU
Q 3V
MCU Self Bias
P 3
DC
T is long to allow MCU to turn on Qand keep V supply to MCUMCU turns off S to shut down (All transistors OFF)
1C
2C
2R
1R
PVV
2R
1R
MCUpT
pT
3V
3VC
DCV
1Q 2Q 3Q
P1 + P2 < P1m + P2m 20% loss
P1 P2
I
P1m
P2m
weak
I
P1
P2
Effect of Mismatched PVs
Future Work: Integrated Converter
DC/DC maximizes energya) from PV. b) to DC/AC.
Communication Unit (CU) shares information.
Centralcontrol
DC/DC
DC
ACMU/CU
DC/DC
MU/CU
Advantages of usingPLC for solar farm
1) No extra wire2) Simple Circuits low cost3) Low power4) Fixed topology5) Low noise6) Low power protocol
Thank You
This research is supported by Ratchadaphiseksomphot Endowment Fund
of Chulalongkorn University (RES560530056-EN).
