k.b. manjunath communication

Experience you can trust.

COMMUNICATIONS

IN

DISTRIBUTION AUTOMATION

K.B. Manjunath

Additional Director, CPRI


Stages involved in Power Distribution

DISTRIBUTION AUTOMATION


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


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.....


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....


Impact of Automation SystemWithout Automation

With Automation


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.


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 ∑

=


Some European ComparisonsSurvey Per Year 2004


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


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


Example of Automated GOS


Example of AutomatedLoad Break Switches/Line Reclosers

SF6 LBS

Vacuum LBS

Air-Break LBS

Line Recloser


Example of RMU(Pad-Mounted Switches)

Generally, if not automation ready, can be retro-fit with motor or solenoid operating mechanism


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


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


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


Wireless Wired

CDMA

GPRS VSAT

RADIO OFC LEASED LINE

PLCC

Between Substation to Control Centre


Between Substation to Distribution Transformers

WirelessAlways on

Wireless (Dial up)

CDMA

GPRS

RADIO PSTN GSM


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.


• 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.


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.


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


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)


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.


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


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)


Communication Technology Overview

• Communication Requirements– Locations– Communication characteristics

• Communication Technologies– Bearer technologies– Wireless technologies


• 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?


Substations

• Communication Characteristics:– 1200 - 9600 bps (higher in future)– Half-duplex– Channel shared (Party Line) for several substations


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)


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


SYSTEMS REQUIRING COMMUNICATIONS


COMMUNICATIONS OPTIONS

SCADA FUNCTIONAL REQUIREMENTS



ENVIRONMENTAL REQUIREMENTS


COMMUNICATION REQUIREMENT ELEMENTS




SCADA TOPOLOGY



REQUIREMENT OF STANDARDS



UCA AND IEC 61850 PROTOCOLS



DESIGN FACTORS FOR COMMUNICATIONS



TRANSMISSION MEDIA CLASSIFICATIONS



Electromagnetic Spectrum for Wireless Transmission



Conducted or Guided Media Transmission

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)