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communication systemstelemetry systemselectronic communication systems
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Experience you can trust.
COMMUNICATIONS
IN
DISTRIBUTION AUTOMATION
K.B. Manjunath
Additional Director, CPRI
Experience you can trust.
INFORMATION WE CAN GET FROM INTELLIGENT METERING
State of art EnergyMeters with AutomaticMeter Reading system& backend I.T. supportcan provide all theseinformation.
SystemMaintenance
Customer Billing
EnergyAccounting
Disconnections& Reconnections
Tariffdesign
SystemLosses
RevenueProtection
LoadControl
DistributionAutomation
LoadForecasting
CustomerComplaints
PowerQuality
Transfers &Vacancies
ManagingCredit
CollectingCash
SystemOperation
SystemExpansion
What a DistributionUtility does
MeteringInformation
Information We Can Get From Intelligent Metering
Experience you can trust.
Distribution Operations– Monitoring the power system– Making adjustments and maintaining the system so that it
can be used reliably, efficiently, and safely– Repairing the system as quickly as possible in response
to incidents such as equipment faults – Tracking and maintaining system reliability data – System planning and expansion to serve new customers
So, within this context, objectivesmay be summarized as follows.....
Experience you can trust.
Objectives• Consistent with India’s National Electricity Policy, to
improve reliability and quality of service of distribution system by – Reducing frequency and duration of power interruptions
to targets consistent with best international practice– Maintaining power quality with respect to voltage and
frequency excursions• To operate efficiently and safely by
– Minimizing power losses– Applying manpower resources effectively
Ideally, these objectives should be obtained at least cost and risk! Now let us consider some of the factors involved....
Experience you can trust.
Reliability Performance Indices
• With moves toward deregulation and open competition, access to accurate and timely outage information is critical in order to maximize operational efficiency, minimize customer complaints, and maintain electric system reliability.
• In this respect, it is common practice to track and benchmark reliability using standard performance indices such as CAIDI, SAIFI, and SAIDI.
• These indices serve as valuable tools to compare utility reliability performance, but care must be taken to ensure they are being calculated in the same manner.
Experience you can trust.
Index Definitions
• System Average Interruption Frequency Index
• System Average Interruption Duration Index
• Customer Average Interruption Duration Index
Served Customers ofNumber TotalonsInterruptiCustomer ofNumber TotalSAIFI=
Served Customers ofNumber TotalDurationson InterruptiCustomer
SAIDI ∑=
onsInterruptiCustomer ofNumber Total
Durationson InterruptiCustomer CAIDI ∑
=
Experience you can trust.
Example Strategy Study Using SAIDI
0.0
1.0
2.0
3.0
4.0
0 1 2 3 4Cost (MUSD)
SAID
I (hr
/yr)
Base
Fuse Saving
Agg
ress
ive
Switc
hing
New
Lin
e D
evic
es
New
Fee
der
Aut
omat
ion
Rec
onfig
urat
ion
FCIs
Tree
Wire
0.0
1.0
2.0
3.0
4.0
0 1 2 3 4Cost (MUSD)
SAID
I (hr
/yr)
Base
Fuse Saving
Agg
ress
ive
Switc
hing
New
Lin
e D
evic
es
New
Fee
der
Aut
omat
ion
Rec
onfig
urat
ion
FCIs
Tree
Wire
Experience you can trust.
Law of Diminishing Return
Reliability Improvement vs. Cost
0
500
10001500
2000
2500
3000
0 20000 40000 60000 80000 100000
Cost
Cus
t Out
age
Min
utes
Im
prov
emen
t
Experience you can trust.
Example of AutomatedLoad Break Switches/Line Reclosers
SF6 LBS
Vacuum LBS
Air-Break LBS
Line Recloser
Experience you can trust.
Example of RMU(Pad-Mounted Switches)
Generally, if not automation ready, can be retro-fit with motor or solenoid operating mechanism
Experience you can trust.
RTU
COMMUNI-CATIONS
SCADA
DMS
UserInterface
DataAcquisition
DMSApplications
SCADAFunctions
SCADA PlatformEnvironment
MaintenanceManagement
DecisionSupportSystems
OMS Crew Management
GIS
Other Applications
DAS Functional/Architectural Overview
Corporate Data Accessibility and
Availability
Experience you can trust.
Future State
Analysis
Crew Management
OutageManagement
Outage Analysis
Outage Reporting
IVR
Reports and History
Operational Diagrams
Switching Management Switching
Planning
Asset Maintenance
CIS
SCADA
Network Operational
ModelNOM
Updates to Network Model and Diagrams
Calls
PlanningERP, GIS
Corporate Asset Data
and Model
Design
r/t stater/t state
Current State Analysis
(Incorporates Load Modelling and
Network Analysis
Typical Distribution Control Room Environment
Experience you can trust.
Communication Options• Between Substation to Control Centre
– Wired• Optical Fibre• Leased Line• PLCC
– Wireless• Radio• CDMA• GPRS• VSAT
• Between Substation to Distribution Transformers– Wireless(Dialup)
• PSTN• GSM
– Wireless ( always on)• CDMA• GPRS• Radio
Experience you can trust.
Wireless Wired
CDMA
GPRS VSAT
RADIO OFC LEASED LINE
PLCC
Between Substation to Control Centre
Experience you can trust.
Between Substation to Distribution Transformers
WirelessAlways on
Wireless (Dial up)
CDMA
GPRS
RADIO PSTN GSM
Experience you can trust.
CODE DIVISION MULIPLE ACCESS• One of the basic concepts in data communication is
the idea of allowing several transmitters to sendinformation simultaneously over a singlecommunication channel. This allows several users toshare a bandwidth of frequencies. This concept iscalled multiplexing. This allows several users to sharea bandwidth of frequencies.
• Code division multiple access (CDMA) is a channelaccess method utilized by various radiocommunication technologies.
• It should not be confused with the mobile phonestandards called cdmaOne and CDMA2000 (which areoften referred to as simply "CDMA"), that use CDMAas their underlying channel access methods.
Experience you can trust.
• CDMA employs spread-spectrum technology and a special coding scheme (where each transmitter is assigned a code) to allow multiple users to be multiplexed over the same physical channel.
• CDMA is a form of "spread-spectrum"signaling, since the modulated coded signal has a much higher data bandwidth than the data being communicated.
Experience you can trust.
FIBER OPTIC COMMUNICATION• Fiber-optic communication is a method of transmitting
information from one place to another by sendingpulses of light through an optical fiber.
• The light forms an electromagnetic carrier wave that ismodulated to carry information.
• The process of communicating using fiber-opticsinvolves the following basic steps:
Creating the optical signal involving the use atransmitter, relaying the signal along the fiber,ensuring that the signal does not become toodistorted or weak, receiving the optical signal, andconverting it into an electrical signal.
Experience you can trust.
Satellite Communication• Heart of the satellite communication system is a
satellite-based antenna in a stable orbit above the earth
• Transponder is an electronics that converts an uplink signal to a down link signal
• Frequency bands for satellite communications L, S, C, X, Ku, K, Ka
Experience you can trust.
Microwave Communication
• Microwave transmission refers to the technique of transmitting information over a microwave link.
Properties• Suitable over Line of Sight transmission links
without obstacles • Provides good bandwidth • Affected by rain, vapor, dust, snow, cloud, mist
and fog, heavy moisture, depending on chosen frequency (see rain fade)
Experience you can trust.
Power Line Carrier Communication
• Most economically viable technology for transferring Meter data to DCU.
• Uses the technique of communicating the data over existing Electrical Lines which carry LT power to the site.
• Employs an ASIC, which accepts digital data & converts it into FSK modulation and transmits it over the power line by sensing a zero crossing of 220V sine wave.
• Typical frequency used for frequency modulation is 132KHz.
Experience you can trust.
Distribution Automation Communication Requirements
• Reliability• Cost effectiveness• Capacity to handle data rates• Ability to reach areas of power outage• Ease of operation and maintenance• Security
Experience you can trust.
Communications Considered
• Telephone (Lease)• Utility-operated Radio (DMB/MARS)• Unlicensed Radio (Point-to-Multi-point)• Distribution Power Line Carrier • Optical Fiber• CDMA/GPRS Cellular Radio (Lease)• MPLS (Lease)
Experience you can trust.
Communication Technology Overview
• Communication Requirements– Locations– Communication characteristics
• Communication Technologies– Bearer technologies– Wireless technologies
Experience you can trust.
• Substations• Distribution Feeders: RMUs, Switches, Auto
reclosures, FPIs• Transformers• Energy Meters• Consumer premises• DA Masters Control Centres• State Load Dispatch Center
Where Is Communication Needed?
Experience you can trust.
Substations
• Communication Characteristics:– 1200 - 9600 bps (higher in future)– Half-duplex– Channel shared (Party Line) for several substations
Experience you can trust.
Feeder Automation
• Switches and other devices can be purchased with integrated RTUs and Communications
• This equipment can be interfaced using a Point-To-Multipoint Spur Radio or Multiple Address Radio System (MARS) connected to a Digital Microwave Backbone (DMB)
Experience you can trust.
Distribution Feeders
• Communication Characteristics– Low data volumes– Unsolicited reporting by exception or change of state– Infrequent data scanning (polling)– Low cost per site
CPRI Power to perform
• Data Acquisition - RTU/FRTU/RMU/FPI’s• Time Synchronization – RTU/FRTU/FPIs• Data Exchange – IT System under RAPDRP• Continous real time storage & playback• SOE• Supervisory Control• Remote database downloading, diag.& config• CIM Compliance IEC 61968• GIS Adaptor – to support native adaptors,
CIM/XML using Model & Data Exchange over IEC 61968 Enterprise SOA based bus
• ISR• LDC & DR• DAS• LAN
SYSTEMS REQUIRING COMMUNICATIONS
SCADA / DMS FOR DISCOMS
DISCOM’S SUB STATIONS & DISTRIBUTION NETWORK
MASTER CONTROL CENTRE DISASTER CENTRE
Load Shed Application (LSA)Fault Management and System Restoration (FMSR)Loss Minim.via feeder reconfiguration (LMFR)Load Balancing via feeder reconfiguration (LBFR)
Network Connectivity Analysis (NSA)Load Flow Applications (LFA)State Estimation (SE)Voltage VAR Control (VVA)
Operation Monitor (OM)Distribution Load Forecasting (DLF)Dispatcher Training Simulator(DTS)