dr. ndr sarma power system automation labeppe.tamu.edu/seminars/seminar_2002_04_5_sarma.pdf ·...

Distribution Automation

Dr. NDR Sarma

Power System Automation Lab

Welcome to the EPPEI Weekly Seminar

What ?

How ?

Why ?

D A

Primary

circuits

Generating Plant

Step-up

transformers

Circuit breakers

Transmission System

Transformers in

Bulk power

substations

Solar or

Wind

Sources

(100KW to

1MW)

One-phase

lateral feeder

Distribution

Transformer

Dispersed

Storage and

generation

(DSG)

Voltage

Regulator

Capacitor

bank

Sub-transmission

system

Distribution

substation

Three-

phase

Primary

feeders

Battery or

Fuel cells,

1 to 25 MW

DSG Sectionalizing

switch

DSG

Photovoltaic

Power supply,

up to 100 KW

Home

Typical Power System

Generation System

Transmission System

Distribution System Distribution System

• substations

• transformers

• circuit breakers

• feeders

• sectionalizing switches

• capacitor banks

• voltage regulators

• DSGs

• customers

- HT customers

- LT customers

Function of Distribution Automation System

Remotely monitors the distribution system,

facilitates supervisory control of devices and

provides decision support tools to improve the

system performance

• SCADA

(Supervisory Control And Data Acquisition)

• Application Functions

Levels of Automation

Substation Level Automation

Feeder Level Automation

Customer Level Automation

Operational problems and Potential Applications of DAS

• Fault location, isolation and Service Restoration

• Maintaining good voltage profile

• Load Balancing

• Load Control

• Metering

• Maintaining Maps

• Fuse-off call operations

• Energy accounting

Recent Buzz words !!

• Outage Management

• Customer Information Management

S u b s ta tio n

A u to m a tio n

F u n c tio n s

F e e d e r A u to m a tio n

F u n c tio n s

C u s to m e r In te r fa c e

A u to m a tio n

F u n c tio n s

D a ta A c q u is it io n F ro m :

- C irc u it B re a k e rs

- L o a d T a p C h a n g e rs

- C a p a c ito r B a n k s

- T ra n s fo rm e rs

S u p e rv iso ry C o n tro l o f:

- C irc u it B re a k e rs

- L o a d T a p C h a n g e rs

- C a p a c ito r b a n k s

F a u lt L o c a t io n

F a u lt Iso la tio n

S e rv ic e R e s to ra t io n

S u b s ta tio n R e a c t iv e

P o w e r C o n tro l

D a ta A c q u is it io n F ro m :

- L in e R e c lo se rs

- V o lta g e R e g u la to rs


- S e c t io n a l iz e rs

- L in e S w itc h e s

- F a u lt In d ic a to rs

S u p e rv iso ry C o n tro l o f:

- L in e R e c lo se rs

- V o lta g e R e g u la to rs


- S e c t io n a l iz e rs

- L in e S w itc h e s

F a u lt L o c a t io n

F a u lt Iso la tio n

S e rv ic e R e s to ra t io n

F e e d e r R e c o n fig u ra t io n

F e e d e r R e a c t iv e P o w e r

C o n tro l

A u to m a tic M e te r R e a d in g

R e m o te R e p ro g ra m m in g

o f T im e -o f-U s e (T O U )

M e te rs

R e m o te S e rv ic e

C o n n e c t/D is c o n n e c t

A u to m a te d C u s to m e r

C la im s A n a ly s is

Candidate Distribution Automation Functions

Control Hierarchy

( From: Turan Gonen, “Electric Power Distribution System Engineering”,

McGraw-Hill Book Company )

Control Center Architecture

…….

..

Modems

FES

1 & 2

DAH

RTUs in

the field

SCADA Host Systems

LAN

MMI 1 MMI 6

Video

Projector

App Server

DMP -1

DMP -2

DT 1 & 2

PERIPHERAL

SERVER -1

Printer

Sharer PERIPHERAL

SERVER -2

Time

Center

Application Functions

• Network Reconfiguration

a) Fault localization

b) Service Restoration

c) Load Balancing

• Integrated Volt-Var Control

• Remote Metering

• Automatic Load Shedding

• Load Management

• Automated Mapping and Facilities Management (AM/FM)

• Trouble Call Management System (TCMS)

• Load Survey and Energy Accounting

Network Reconfiguration - Fault Localization

• Locates faulty section in a radial distribution feeder by

operating “Load Break Switches” on a feeder

• Localization is faster compared to manual determination of

faulty section

Fault Illustration:

A radial feeder

Fault localization Fault

CB Close

LB Sw Close

Network Reconfiguration - Service Restoration

• Restores service to non-faulty feeder sections by reconfiguration

• Considerations

* Presence of alternate paths

* Operation of LB switches

* Need to have remotely controllable switches

* Restoration based on

- satisfaction of current and voltage constraints

- minimum switches

- minimum losses

Network Reconfiguration - Load Balancing

• Composition and hence consumption patterns of loads on

different feeders are different

• To distribute loads among transformers/feeders

• Remote control of switches for reconfiguration

Load Balancing - Illustration

Feeder 1

Feeder 2

Initial

configuration

Final

configuration

Integrated Volt-Var Control

• Applied on feeders with capacitors and voltage regulators

• Control of capacitor banks and voltage regulators

• Schedule for switching and tap control

• To meet reactive power requirements and reduce losses

Remote Metering

• Uses of electro-static meters

• Customer meter reading

• Facilitates Multiple tariff

• Detection of Meter tampering

• More justifiable at HT (high value) Customers

Automatic Load Shedding

• Under Frequency based load shedding

• Sensing Frequency through transducers

• Load shedding based on the frequency drop, current loading

conditions and priority of the load

• Closed loop function at RTU level

(6 to 7)

(7 to 8)

(8 to 9)

(9 to 10)

Schedules for Power

cut on Feeders

Illustration

Load Management - Scheduled power cuts

• Gap between generation and demand

• Schedule power cuts on rotation

• Automatic load shedding based on schedules

• Facility to change the schedules

Load Management - Emergency based load shedding

• Gap between power generation and load demand due to

sudden contingencies

• To shed the loads based on the relief required

• Identification of loads to be shed based on

- current load magnitudes

- priority of the load

- time when last shed

• Shed the load based on the above factors

Load Management - Agricultural load control

• Importance of Agricultural load

• Separate schedule for Agricultural loads

• Ag. Loads categorized into groups

• Schedule for each group

• Shed the load based on the schedule

• Use of one-way radio switch

- Accepts a command to shed

- Restores automatically

Automated Mapping and Facilities Management (AM/FM)

• Display of geographical Maps

• Dynamic info on Maps

• Layering, Zooming, Scrolling and Panning

• Historical data on Devices

(From T&D World, Oct 2001)

(From T&D World, Oct 2001)

Trouble Call Management System (TCMS)

• Responds to customer complaints

• Acceptance of interruption/restoration data from the operator

• Distribution Transformer trip/close info from SCADA

• Determination of source of interruption

• Improvement of response time to customer complaints

Load Survey and Energy Accounting

• Availability of continuous data on loads etc.,

• Determination of Load Patterns

• Data for planning

• Detection of abnormal energy consumption pattern

• Identification of high loss areas

Overall Schematic Diagram of Gachibowli DA Project

Why Distribution Automation ?

Benefits

- Tangible

- In-tangible

Tangible Benefits

Substation

Automation

Feeder

Automation

Customer interface

Automation

Reduction in O&M Costs of LTC

Operation for:

• Routine LTC Operations

• Non-Routine Operations

Reduction in Capital Expenditure

due to:

• Deferment of additional feeders

• Effective utilization of existing

feeders

Reduction in O&M Costs of:

• Regular Meter Reading

• Reprogramming of Meters

• Service Connect/Disconnect

• Processing of Customer Claims

Reduction in O&M Costs for:

• Routine Relay Testing

• Relay Setting


• Routine Data Collection

• Non-Routine Data Collection

• Data Analysis

• Testing of Data Logging Devices

• Repair of Data Logging Devices

Increased Revenue Due to:

• Loss Reduction due to Feeder

Reconfiguration

• Loss Reduction due to Capacitor

Banks Automation

• Faster Service Restoration

Reduction in Capital Expenditure

due to:

• Deferment of additional substation

facilities

• Effective utilization of substation

facilities

Reduction in O&M Costs of Breaker

switching for:

• Routine Operations

• Non-Routine Operations

Increased Revenue Due to:

• Reduction of System Peak Load

• Tamper Detection to Reduce

Electricity Theft

• Reduced Payments for Customer

Claims


• Fault Location and Isolation

• Service Restoration

• Routine Switching Operations

• Recloser Setting

• Recloser Testing

• Data Collection

• Data Analysis

• Feeder Reconfiguration

• Capacitor Banks Inspection

Summary of cost/benefit Analysis Results (done in 1991)

based on tangible benefits

Present Value of

benefits ($) 177,393 423,260 2,913,258

Present Value of

costs ($) 166,764 555,000 10,934,353

Benefit/Cost

Ratio 1.06 0.76 0.27

Function

Category

Substation

Automation

Feeder

Automation Customer interface

Automation

Details of the area : 32,000 customers with electric and gas meters with a mix of 53 % residential,

8 % commercial 37% industrial and 2% agricultural.

Peak demand : 124 MW

Area served by three major substations (230/21 kV, 115/12 kV, 60/12 kV)

with 13 primary feeders circuits (eleven 12kV and two 21kV) in the area

David L. Brown, et al., “Prospects For Distribution Automation at Pacific Gas & Electric

Company”, IEEE Transactions on Power Delivery, Vol. 6, No. 4, October 1991, pp 1946-1954.

Improved Service

Reliability Applicable Applicable Not Applicable

Improved Customer

Satisfaction Applicable Applicable Applicable

Better Information

for Engineering and

Planning

Applicable Applicable Applicable

Benefit

Category

Substation

Automation

Feeder

Automation

Customer interface

Automation

Improved Public

Safety Applicable Applicable Not Applicable

Strategic or

Marketing

Advantages

Applicable Applicable Applicable

Improved Public

Image Not Applicable Not Applicable Applicable

Intangible Benefits

Summary

• What is Distribution Automation ?

• How do you do Distribution Automation ?

• Why Distribution Automation ?

Monitor, Control, Decision support tools

SCADA and Application Functions

Tangible and Intangible benefits

dr. ndr sarma power system automation labeppe.tamu.edu/seminars/seminar_2002_04_5_sarma.pdf ·...

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