The document outlines a presentation on power system communications and smart grid communications. It discusses various wired and wireless communication technologies used in power systems like power line carrier communication, fiber optics, radio systems, and cellular networks. It also covers smart grid communication requirements, infrastructure including home, neighborhood and wide area networks. Standards like IEC 61850 and DNP3 used for information exchange are also summarized.

1. National Power Training Institute
Power Systems Training Institute
(Ministry of Power, GoI)
Bengaluru, India
R SENTHIL KUMAR
Assistant Director
POWER SYSTEM COMMUNICATION

2. PRESENTATION OUTLINE
• POWER SYSTEM COMMUNICATIONS
• SMART GRID COMMUNICATIONS
• SMART GRID COMMUNICATION INFRASTRUCTURE
• DEDICATED AND SHARED COMMUNICATION
CHANNELS
• WIRED COMMUNICATIONS
• WIRELESS COMMUNICATIONS
• STANDARD AND PROTOCOLS
• IEC 61850 DATA STRUCTURE

3. COMMUNICATIONS
A Communication system consists of a
transmitter, a receiver and communication
channels. Type of medias and network
topologies in communications provide
different opportunities to advance the speed,
security, dependability, and sensitivity of
Power system.

4. Comparison of Communications
• Power Line Communication
Advantage:
Economic, suitable for station to station
communication, Equipped installed in utility
owned area.
Disadvantage:
Limited distance of coverage, Low bandwidth,
inherently few channels available, exposed to
public access

5. Comparison of Communications
• Microwave Communication
Advantage:
Cost effective, reliable, suitable for establishing back
bone communication infrastructure, high channel
capacity, high data rates
Disadvantage:
Line of sight clearance required, high maintenance
cost, specialized test equipment and need for skill
technicians, signal fading and multipath
propagation.

6. Comparison of Communications
• Radio System Communication
Advantage:
Mobile application, suitable for communication with
areas that are otherwise inaccessible.
Disadvantage:
Noise, adjacent channel interference, change in
channel speed, overall speed, channel switching
during data transfer, power limitation and lack of
security.

7. Comparison of Communications
• Satellite System Communication
Advantage:
Wide area coverage, Suitable to communicate with
inaccessible areas, cost independent of distance,
low error rates.
Disadvantage:
Total dependency to remote location, less control
over transmission, continual leasing cost subject
to tapping,

8. Comparison of Communications
• Fiber Optics Communication
Advantage:
Cost effective, High Bandwidth, High data rates,
immune to electromagnetic interference, Already
implemented in telecommunication, video data,
SCADA, Voice transfer etc.,
Disadvantage:
Expensive test equipment, failure may difficult to
pin-point, can be subject to breakage.

9. SMART GRID COMMUNICATIONS
• Bi-directional flow of information (along with
electricity) – for effective control of generation
and consumption
• Real-time information: Paves way for active
consumer participation
• Technologies used at each level of operation to
be in sync with data rate, permissible latency,
security and timing requirement of respective
application
• Communication protocols must account for
specific needs of the power system applications

10. Smart Grid Communication Requirements
• Security-Ensure secure information storage,
transportation, privacy, avoid cyber attacks
• Reliability, Robustness and Availability-Timely
availability of time critical information,
robustness to distortions and channel noise
• Scalability-It should be flexible enough to add on
new web services and protocols with increasing
penetration of renewable and modernization
• Quality of Service (QoS) -Reduce packet drops,
minimize latency and delays

11. Smart Grid Communications: Key Considerations
• Availability during power outage –more so during
natural calamities –ensure observability of the network
not on outage
• The technology in use should in itself have low power
requirement
• Secured and resilient to attacks and intrusions
• Scope for open standards and enable interoperability
• Choice of technology based on density of nodes, last
mile connectivity, cost of deployment
• Choice of technology: Licensed versus Unlicensed

12. Information flows in Smart Grid
Two way information flow between -
• Sensors and electrical appliances to smart
meters-HAN-Wireless : ZigBee, 6LowPAN, Z-
Wave-Wired: Power line communication-
(Mostly) Unlicensed technologies
• Smart meters to utility’s data center-WAN,
NAN-Internet, Cellular Technologies (2G,3G,
4G)-(Mostly) Licensed technologies

13. Smart Grid Communication Infrastructure
• Customer: Home Area Network (HAN)Devices -Smart
meters, thermostats, PCs, building automation, pumps
Technology -ZigBee, WiFi, Open HAN, Home Plug
• Distribution: Neighborhood Area Network (NAN)Devices -
Smart meters, relays, distribution automation Technology -
WiMAX, PLC, Cellular
• Transmission and Operations: Wide Area Network
(WAN)Devices -EMS, WAMS, lines, towers, sensors and
actuators Technology -IEC 61850, DNP3, SANET, Satellite
• Markets-Enterprise and external Participants -Retailers,
Aggregators, Regulators, Customers Technology -Internet
protocols

14. Dedicated and Shared Communication Channels
• Dedicated-secured communication, exclusive link between
source and destination, lesser latency, expensive Example:
Differential protection of transmission lines -
communication between differential relays (blocking
signals)
• Shared-Message sent by the source is received by all
devices connected to the shared channel. An address field
in the message specifies for whom it is intended. -higher
latency but economic, higher utilization of available
resource Example: Communication network inside a
substation, star or ring connection of bay controllers and
monitoring equipments (CT, PT)

15. Wired Communication
Power Line Carrier Communication (PLCC)-
-Sending data simultaneously with electricity over
same medium
-Minimal added installation
-Line matching unit injects signals Into HV
Transmission lines or LV and MV Distribution lines
-Message captured by line traps-Originally used for
low-rate SCADA, now being used in Home
Automation

16. Wired Communication
Power Line Carrier Communication (PLCC)-
-High data rate and capacity: 200 Mbps within
homes, but low bandwidth for NAN restricts
usage
-Challenge from discontinuity-transformers, circuit
breakers, faults
-Shared medium –data transmissions are broadcast
in nature-security and privacy issues
-Transmission medium is harsh and noisy –adds
coloured noise, severe signal distortions. Channel
modelling is a challenge.

17. Wired Communication
Power Line Carrier Communication (PLCC)-
-Ultra Narrow band (UNB):below 3KHz, low data
rate, high connectivity over long distances
-Low Data Rate (LDR) Narrow Band (NB): Between
3-500KHz, single carrier based, upto10kbps
-High Data Rate (HDR) Narrow Band (NB): Upto1
Mbps, for NAN communication
-Broadband PLC: Above 1.8MHz, short range, used
in HAN

18. Wired communication
• Twisted Pair-two twisted copper cables each with outer
PVC or plastic insulator –up to 1.2 GBps -broadband
services
• Coaxial Cables-Outer coaxial conductor provides effective
shielding from external interference -reduced losses from
skin effect –up to 10 MBps
• Optical Fibres - Core, cladding and buffer coating -internal
reflection -less signal degradation than copper wires, no
interference (EMI)-lesser weight than copper but high cost
of installation -used for long distance transmission –no
need for repeaters up to 100 Km-high capacities up to 1
Tbps-security high because of obscurity

19. Wired Solutions
• DSL(Digital Subscriber Lines): High-speed
digital data transmission technology that uses
the wires of the voice telephone network,
Frequency band 0 -2.208 MHz, inexpensive,
scalable, poor data security, high latency,
same applications as PLC
• Ethernet: Frequencies -16 MHz, 100 MHz, 250
MHz, 500 MHz, 600 MHz, 1 GHz, 1.6-2.0 GHz.

20. Wireless Communication
• Radio Communication-Alternative to expensive fibre optic and
copper wire for long range, limited bandwidth1. Ultra High
Frequency (300 MHz -3 GHz)2. Microwave (3 GHz -30 GHz)
• Cellular Technology-service area divided into cells, each cell
has a transceiver to control and communicate with users
within a cell, operates on CDMA, communication between
mobile objects -even when the object moves across different
cells. Technologies -3G, GPRS, GSM. -In India 900, 1800, 2100
and 2300 MHz, short technology life cycle
• Satellite Communication -Widely adopted for SCADA,
microwave network with satellites acting as repeater, key
challenge is delay

21. Short Range Wireless Solutions -
6LoWPAN
• Low power RF in 800 MHz, 900 MHz and 2400 MHz
bands
• Applications: AMI (NAN), SCADA/EMS (NAN),
SCADA/DMS(NAN), Building automation, Microgrids,
Distributed generation, Electric Vehicles
• Lightweight, versatile -can be used with any physical
and data link layer
• Scalable
• Low power RF unreliable due to uncertain radio
connectivity, battery drain, physical tampering

22. Short Range Wireless Solutions -
ZigBee
• Short range solution (10-100m), same application
areas as 6LoWPAN
• Low data rates: 20kbps, 250 kbps
• Frequency bands ~ 868 MHz (20 kbps) for EU, 915 MHz
(40 kbps) for US and AUS and 2.4 GHz (250 kbps)
worldwide
• High market penetration in home automation ~ Low
cost of modules
• Low reliability, poor interoperability with non-ZigBee
devices
• Low power consumption compared to other sub GHz
protocols

23. Short Range Wireless Solutions -
ZigBee
• Ideal technology for smart lightning, energy
monitoring, home automation, and automatic
meter reading
• Capable of being connected in a mesh of large
number of devices ~ 1000 nodes and more
• low processing capabilities, small memory size
• Interference from other devices using the
license free ISM frequency band (2.4GHz) like
WiFi, Bluetooth and Microwave

24. Short Range Wireless Solutions -WiFi
• Frequency 2.4 GHz, limited range, low power RF
• Applications: Automatic meter reading (AMR),
AMI -NAN, home automation
• Higher power consumption than ZigBee (WiFi ~
700 mW, ZigBee ~ 100 mW)
• Based on IEEE 802.11 standard for WLAN,
optimized for fast data rates -higher than other
RF technologies
• Cost effective

25. Other Low Power Short Range
Wireless Technologies
• Bluetooth-2.4 GHz, only connects two devices at
any time, extremely short range, applied mostly
for reading meter data
• Infrared-2.4 GHz, extremely short range, line of
sight communication, inexpensive, low power
consumption, application-meter reading
• Z Wave -865 MHz to 956 MHz, compared to
ZigBee expensive and not scalable, poor
penetration in IndiaApplications: SCADA/EMS,
SCADA/DMS, microgrids, substation automation

26. Long Range Wireless Solutions
• WiMAX: typically coverage of 20kms or more for 1.8
GHz link, based on IEEE 802.16 standard, Data rates up
to 140 Mbps, low latency (10-50 ms)
• Low Power Wide Area (LPWA): Frequency -TV
spectrum, 900 MHz, 2.4 GHz, 5 GHz, Applications:
SCADA/EMS, SCADA/DMS, Substation automation
• Satellite Communication: Frequency -1 to 40 GHz,
affected by weather, WAMS application
• Long Wave Radio: Typically 100 -200 kHz, extremely
high range, reliable, propagation affected by obstacles

27. Comparison of commonly used
technologies

28. Comparison of commonly used
technologies

29. Comparison of commonly used
technologies

30. Communication Standards and
Protocols
• A communications protocol is a standard rule for data
representation and data transfer over a communication
channel.
• If devices use different protocols they will not be able to
share data with each other.This was a problem in earlier
versions of SCADA networks where devices from different
vendors used different manufacturer specific protocols
(proprietary protocols).
• Open standards for communications enables seamless
interoperability between devices, this brings many
advantages. Vendors can supply off-the-shelf SCADA
solutions that can be easily modified and used.

31. Open Standards for Smart Grid

32. Standards for Information Exchange
DNP3:
-Distributed Networking Protocol
-Communication between substation data
acquisition and control equipments
-Used by control centers, RTUs, IEDs
-Reliable but not secure from attacks
-Master DNP3 station sends request and Slave
DNP3 stations respond to these request, slave
can also transmit message without request
-Recently adopted as IEEE standard 1815-2010

33. Standards for Information Exchange
IEC 61850
-Framework for substation automation, addresses
interoperability of IEDs
-Uses an object model to describe the information available
from different pieces of substation equipments
-In addition to defining a protocol, specifies a data structure
-For every physical device, logical devices within it are
specified. Each logical device is then mapped to 86 different
classes of logical nodes as defined in IEC 61850. For a IED
with protection logic, the logical nodes could be -distance,
over current, differential, etc.

34. IEC 61850 Data Structure