Power Line Communication from Home Automation to Solar Farm Monitoring Ekachai Leelarasmee Chulalongkorn 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 carry high freq data signal • Data rate from 1Kbps – 200Mbps 230KVac 220Vac 23KVac www.prime-alliance.or g
PLC signal on AC 220V 622V 0.4V 80kHz
Voltage (Parallel) Mode PLC AC line PLC PLM PLM PLM data Device Device Device Device = Appliance, Computer, ADSL, etc PLM = Power Line communication Module
PLM 80-90kHz 10 μ F 6 8 μ H . 10 1 : Tx Filter Data 220V ac DSP 100 Ω 470nF Rx 470 μ H 15nF 64Kbps, OFDM
PLC classification Type Narrow Band Broad Band Freq. 3-500kHz 2-25MHz Data 2-128Kbps 10-200Mbps Range > km < 300m Uses Monitor/Control High Speed Data STD PRIME,G3,X10 Home Plug Av App Smart Grid Home Network
Home Automation (narrow band < 500kHz) Low speed <128kbps Control & Monitor X10, LonTalk www.sentec.com
Home Area Network Broadband <25MHz High speed<200Mbps internet Home Plug Home Plug AV www.aztech.com
Street Lighting Long range Lamp maintenance & dimming www.smartlighting.com
EV Charging station www.greenvity.com
Smart Grid Narrow band, Long range MDM OM DSM etc PRIME, G3
Problems with PLC 1) Noises 1.1) Motor & Switch (intermittent) 1.2) Switching Power Supply (Periodic impulse) 2) Unknown Topology 2.1) Line characteristic varies 2.2) Frequency & Time dependent 2.3) Multiple reflection (coupling loss)
Smart Grid Technology low data rate (32kbps), real time, long range
PoweRline Intelligent Metering Evolution Open International PLC Standard for Advance Metering, Grid Control and 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 RF (Zigbee) 220V AC in 220V AC out PLC (PRIME)
Advance Metering Infrastructure (AMI) Data Corporate Concentrature RF, Optic Utility Network (BN) Internet PLC SW SN SN SW SN
PRIME Protocol Layer 41.992KHz – 88.867KHz 128Kb/Sec OFDM
PRIME OFDM
PRIME MAC Frame Structure
Solar Farm Monitor + - 20-100V 50-200W 8MW 86668 PV panels: fixed topology
World Bank 2012 Renew energy projects Global (MW) Thailand (MW) Bio 1277 39 Hydro 31060 0 Wind 28900 127 Solar 7695 326
Blackout 22 May 2013 Lightning strike on 500KV Not enough local Power generation
Multi-String Topology − 8 20 PVs AC Inverter I I AC P P 1 n DC − 8 20 PVs AC DC PV’s are not identical but must operate at the same current � un-optimal
Mismatched PV panels defect, cloud, trees, airplane, direction crack, dust, leaves, aging, temperature
Effect of Mismatched PVs P 2 weak P 1 I P 2m P 2 P 1m P 1 I I P 1 + P 2 < P 1m + P 2m 20% loss
Solar Farm (Health) Monitoring Control center AC MU MU CU DCU CU DC AC MU CU MU CU DCU DC MU : Monitor Unit (V,I,Temp) CU : Communication Unit DCU: Data Concentrator Unit
RF 433MHz or 2.4GHz Control center AC MU CU MU CU DCU DC AC MU CU MU CU DCU DC Expensive, Fragile & Complicate
Serial Mode PLC AC MU MU CU DCU CU DC AC MU CU MU CU DCU DC
AC Current Mode PLC (analog tech) Control Center AC MU CU MU CU DCU DC AC MU CU MU CU DCU DC Low cost: uses current transformer for coupling high frequency current signal
Pulse PLC (digital tech) Control Center AC MU CU MU CU DCU DC AC MU CU MU CU DCU DC Low cost. Toggle switch to transmit data
1) AC Current Mode PLC I ac MU MU Tx Rx Rx Superimpose AC Current onto DC Current I I I Z = ∞ = Z 0 ac i o i o V Rx V Tx o i PV & INV must be short circuit at carrier frequency ω o
PLC Current Coupling Circuit I I ac ac L ,L m k L C 1 2 V V i o C 1
Tx Mode = ∞ Z to couple current o Ideal Ideal I I I I ac ac ac ac Z Z o o L m L L k m L 1 L C C 1 2 2 V i = I j ω C V i 2 i 1 1 2 = ω = ω o o + (L (L L ))C (L � L )C � 1 m k 2 1 m 2
Rx Mode = Z 0 to avoid loading DC line i Ideal Ideal I I I I ac ac ac ac Z Z i i L m L L C m k 2 L C L C 1 1 1 2 V o V C o 1 − jI C 1 ac 2 = = = ω ; V V o o i ω C C L C o 1 1 1 1 2 − 1 ω L C 1 2 o k 2 = • ω o 2 + (L L )C − 1 ω (L � L )C 1 k 1 o 1 k 2
50W Amorphous PV panels
Carrier frequency Z 3 Ω PV 250kHz ω 2.2 0.8 μ o 0.81A 980 Z pv
Test Experiment for simulation #8 #1 = L 84 μ m = L 36 μ 3 Ω 3 Ω k = R 50 s MU CU MU CU DCU = R 10k L I I ac ac = = L 220 μ H ; C 5.22nF 1 1 L ,L m k = = C 1.39nF; R 50 2 s L C 1 2 = R 10K ; V V L i o = = V 1V ; I 2.18mA C 1 i ac ac ac = Energy loss per PV 14 μ W
Monte Carlo Simulation 50 simulations, 20% over 3 sigma Gaussian Distribution V o V i
Amplitude Shift Keying (ASK) 0 1 1 1 250kHz 40 μ S 40 μ S 40 μ S 40 μ S 4 μ S Data Rate = 25kbit/sec
MU & CU Circuit − 50V + 1 M Ω 3V REG CU V V i o D o MCU ADC D 10k Ω GND i Consume 50uA (2.5mW) while idle
Low Power MU & CU Circuit M1 M1 on on − 50V + to 3V CU V V ADC i o D o ADC MCU D Gnd i M2 M1 M1 is on to wake up MCU MCU turns on/off M2 to keep power on/off to save power
Low Power Communication Protocol AC MU CU MU CU DCU DC CU DCU wake (111) addr & instr ack response sleep
Pulse PLC #n # 1 AC V V V DCU D MU CU MU CU DC A switch closes temporarily to create a pulse that propagates through the DC Power Line. = − V (n 1)V if one PV switch closes D = V 0 for all PV if DCU switch closes Thus DCU can broadcast data to all PVs PV can reply to DCU only
Ideal Waveforms: 8 x (50V) PV → DCU PV 0 1 0 400V V 300 μ 600 μ DCU 8 μ → PV DCU 50V V pv
Pulse shaping due to PV Capacitor DC Line PV = C 65nF + = V 50V pv MU V C pv = → I I 0.015 0.5A − ph ph = → T 6.5 220 μ S Close Open r Close Data Rate V 1 < 8 μ C V + T pv pv r = 8 μ S T r I = 4.4kpulse / s ph
Ringing due to transmission line effect AC Transmission Line DC cause ringing + = = V L 1.475 H / m, C μ 11.3pF / m DCU −
Ringing through DC Line = R 10; L= ; C close 15m cable 35m cable 1.8MHz
Ringing Suppression at DCU + R Y Z V o DCU C Y − = R 410 Ω to match Z Y o = C 2nF to block DC Y
Ringing Suppression at the Switch Soft Switch Hard Switch + − + − V V pv pv R C V V pv pv
50W Amorphous PV panels
V DCU a) Hard Switch (IRFS630) b) Terminate DCU with 410 + 2.2nF c) Soft Switch with 1.5K & 150pF d) Soft Switch under weak sunlight
Negative edge detector in Q is OFF when idle (zero power) out ON when there is a neg. pulse T P DC line V 3V PV T p R 2 PV Q C 1 R panel ON OFF / 1 μ C Switch C 2
3V T Design p Δ PV 3V R Eq. 2 Q C 3 Δ 1 R 1 3 Δ P C 2 C R 1 2 = ≈ ≤ ∆ ∆ ; ∆ ∆ 0.7 P PV P + + C C R R 1 2 1 2 ( ) = + + T (R R )(C C )ln ∆ / 0.7 P 2 2 1 2 = = = = = R R 10K Ω ; C 470pF; C 4.7nF; ∆ 80V 1 2 1 2 PV = = = ∆ 7.27V ; ∆ 3.6 3V; T 170 μ S P P
Experimental Result Strong Weak Broadcast One MU by DCU responses
Edge Detector with Regulator DC line 3V 40V R 2 PV Q C 1 panel R 1 MCU C 2
Edge Detector with Regulator DC line 3V 40V R 2 PV Q 3V C 1 panel R 1 MCU C 2
MCU Self Bias V V PV DC R R Q Q Q 2 2 1 2 3 C T 1 p R R 1 1 C 3V T p C 2 MCU 3V T is long to allow MCU to turn on Q P 3 and keep V supply to MCU DC MCU turns off S to shut down (All transistors OFF)
Effect of Mismatched PVs P 2 weak P 1 I P 2m P 2 P 1m P 1 I P 1 + P 2 < P 1m + P 2m 20% loss
Future Work: Integrated Converter Central control DC/DC DC/DC AC MU/CU MU/CU DC DC/DC maximizes energy a) from PV. b) to DC/AC. Communication Unit (CU) shares information.
Advantages of using PLC for solar farm 1) No extra wire 2) Simple Circuits � low cost 3) Low power 4) Fixed topology 5) Low noise 6) Low power protocol
Thank You This research is supported by Ratchadaphiseksomphot Endowment Fund of Chulalongkorn University (RES560530056-EN).
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