Scad A

SCADA Supervisory Control And Data Acquisition

System for National Power Control Center

NTDC, WAPDA Islamabad

Data Acquisition System

Data/Voice Transmission Channel

PLC, Microwave, Satellite, PTCL, Mobile

Two Computer Systems

- One at NPCC Islamabad both for NCC Islamabad & Regional Control Center North

- One at Regional Control Center Jamshoro

Computers are based on Computers are based on 1980’s1980’s technology Memory of the computer technology Memory of the computer

at NPCC/RCC is at NPCC/RCC is 4 Mbytes4 Mbytes. . Secondary Secondary

memory(H.D) memory(H.D) 340 Mbytes 340 Mbytes

Both Systems Linked via 6 Channels through Wapda’s Analoge Microwave

system

PresentNPCC, NTDC SCADA System

• NPCC Computer system connected with 25 RTUs– Regional Control center (North) is Using same computer .

• Regional Control Center (south) heaving separate computer system connected with 11 RTUs

– It has a Front end to Front end link with NPCC (subscription link)

• In-plant SCADA system at Tarbela further connected with 11 RTUs

– It has a Front end to Front end link with NPCC only for selected values ( due to less memory of NPCC SCADA system) from selected RTUs via single subscription link through PLC.

Network Configuration

Point to Point

Multi Drop

Series

Star

Series loop

Subordinate terminals

Limitations for RTU interfacing 40 channels were

designed 34 already allocated.

Data acquisition Facilities 1/2

Analogue Values– MW– MVAR – Voltages– Frequency– Tap position

Data acquisition Facilities page 2/2

Status ( Indications )• Breaker Open / Close and error Status (X)• Isolator Open / Close and error Status (X)• Protection signals (only for IPPs)• Synchro-check Signals ( Freq, Phase and Voltage difference)• AGC signals

Remote Control FacilitiesRemote Control Facilities

Remote Control OperationRemote Control Operation – Breaker Open / Close (Only for 500Kv breakers)– Tap regulation (Only for 500/220 Kv Transformers.)

– Automatic Generation Control (Facility limited due to poor communication and limited interfacing )

Remote Control OperationRemote Control Operation – Breaker Open / Close (Only for 500Kv breakers)– Tap regulation (Only for 500/220 Kv Transformers.)

– Automatic Generation Control (Facility limited due to poor communication and limited interfacing )

Operation Pages

Display types– Single line diagrams– Curves– Events– Alarms– Reports, power system– Post mortem review (only for analogue

values on 30 Seconds Resolution)

Storage Capacities

Values and indication Storages

Values: Storage

Time

• 10 Seconds Instant values only for AGC = 250 : (45 min)

• 30 Seconds Instant =1000 : ( 1Hrs )

• 15 Minutes Instant = 650 : (5 days)

• One Hour Instant ALL : (5 days)

• One Hour Indications ALL : (5 days)

1. How can load Despatch system sustain and ensure !Optimization of costs of GenerationMinimization of transmission lossesQuick restoration of supply Minimization of outages Avoiding major collapseQuality and reliability of supply Voltage and frequency control By upgrading existing SCADA & Tele-communication with latest version

Technical Features(SCADA Hardware)

Existing System Proposed New System

Make : Modcomp USA /ABB Latest Available At the time of Procurement

Operating System MAX-IV

( DOS environment)

Window Based

(User Friendly)

Capacity : 4 MB Latest Available At the time of Procurement

Present day PC RAM : 1000 MB

Hard Disk Space : 340MB Latest Available At the time of Procurement

PC Hard Disk : 40000- 80000 MB

Speed : 30 MHz Normal PC Speed > 2000 MHz

VDUs are of special design,

Replacement of VDU is due ( Life was 10 years)

Cost is very High, being of special design

VDU are of common design.

Easy replacement being readily available.

Low Cost.

Interfacing with PC is not provided in the system. Can be easily Interfaced with PC.

Spares no longer manufactured becoming difficult to maintain

Technical support from manufacturer if required may not be available in future.

In new system this problem will be solved.

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Technical Features(SCADA Software)

Existing System Proposed New System

New application Software cannot be used due to less memory and speed.

New Software would be easy to run.

The following new software are proposed which are essential for NPCC.

i. Unit Commitment and economic despatch.

ii. Automatic Generation control.

iii. Optimal Power flow.

iv. Load Forecasting Software.

v. Training Simulator software.

vi. On line Load flow studies.

vii. Contingency Analysis

2/4

Technical Features(Remote Terminal Units - RTUs )

Existing System Proposed New System

Only ABB Collector 300 and Collector 400 RTUs can be Interfaced

RTUs of any make & type can be interfaced.

Cost Per RTU : Rs 12.5 Mln.

Existing Stations( without RTUs) : 9

Future stations up to 2008 : 17

Cost of 26 RTUs ( 9 + 17) : Rs. 325 Mln.

Rs. 3 Mln.

Rs. 78 Mln.

Expensive Transducers are required due to software limitation and is proprietary item of ABB

Low cost transducers can be used.

Expensive spares have to be purchased from manufacturer being proprietary item of ABB

Cheap Spares can be purchased from open market.

Limit to interface number of RTUs is 40, which is about to exhaust.

Communication Lines Interfacing Limit of both RTUs and Lines would be enhanced.

Globel Positioning system ( GPS ) for time clock cannot be interfaced.

GPS is easy to interface.

Only 6 – channels for interfacing with other system.

Enhanced number of channels.

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Technical Features(Telecommunications)

Existing System Proposed New System

Analogue Microwave backbone from Islamabad to Jamshoro

Digital Microwave communication highway from Islamabad to Jamshoro.

Number of Channels : 60 Number of Channels : 630

Channels Capacity already saturated Channels capacity enhancement possible up to 1890 Channels.

Spares no longer manufactured, Becoming difficult to maintain.

Spare availability shall be ensured for about 15 years.

Failure rate of system is on increasing trend. --

System is working in 1 + 0 configuration at several points instead of 1 + 1 requirement.

--

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Status of RTUs

(Installed)500 kV ( 13 Stations )

Tarbela Guddu Ghazi Barotha ( Not Comissioned )

New Rewat Dadu Hubco

Lahore Jamshoro Rousch

Gatti Muzzafar Garh ( Not Comissioned )

New Multan Shaikh Mohammedi ( Not Comissioned)

220 kV ( 21 Stations )

Mardan Nishatabad Islamabad Pesh Road ( Not Comissioned)

Burhan Kala Shah Kaku Daud Khail ( Not Comissioned )

Gakhar Bund Road AES Lal pir

Mangle NGPS Multan AES Pakgen

New Kot Lakhpat Sibbi KAPCO

Yousaf Wala Hala Road Uch Power

Jaranwala Road Sialkot ( Not Comissioned ) Chashnup

132kV (11 Stations )

Warsak GTPS Faisalabad Fuji Kabirwala

Kel Saba Power Liberty Power

Kotri Chasma Hydro Power ( Not Comissioned) Habibullah coastal

Sepcol Japan ( Not Comissioned )

1/2

Status of RTUs

(Additional Requirement upto year 2008 )

Existing Stations without RTUs

220 kV ( 8 Stations )

Bahawalpur Bannu Ludewwala

Quetta Industrial Ravi Sumundri Road

Sarfraz Nager Vehari

132 kV

Lakhra

Future Stations to be commissioned upto 2008

500 kV ( 4 Stations)

Gujranwala Sahiwal Rahim Yar Khan

KESC

220kV ( 13 Stations )

Shahi Bagh Fateh Garh Islamabad University

Nowshera Indutrial Mansehra Mustung

Ghazi Road Lahore Chiniot Road Kharian

Shikar Pur T.M Khan (Hydrabad)

Chichawatni D.G Khan

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