POWER GRID CORPORATION OF INDIA LIMITED

A SUMMER TRAINING REPORT ON

SWITCHYARD PROTECTION

POWERLINE CARRIER COMMUNICATION

AND APPLICATION OF SCADA IN SUBSTATION CONTROL

POWER GRID CORPORATION OF INDIA LIMITED

400 KV S/S, SWITCHING STATION, 12.6 KM MILESTONE ON SHAMSABAD ROAD, P.O. SHYAMO, AGRA-282003 U.P.

CONTENTS Power Grid: At a glanceAwards & AchievementsCertificatesTransmission/ subtransmission projects Research & developments Activities Mission

Part A : “SWITCHYARD PROTECTION”• Single line diagram• Circuit Breaker• Lightning Arrestor• Isolator• CVT• Reactores• Other Switchyard Equipments

PART B : POWER LINE CARRIER COMMUNICATION

• PLCC• Line Trap

PART C : APPLICATION OF SCADA IN POWER GRID

• What is scada?• Architecture & Functionality

BIBLIOGRAPHY

POWER GRID AT A GLANCE POWERGRID, the Central Transmission Utility (CTU) of the country, is engaged in power transmission business with the mandate for planning, co-ordination, supervision and control over complete inter-State transmission system.

This gigantic transmission network, spread over length and breadth of the country, is consistently maintained at an availability of over 99%.

POWERGRID, as on July 2009, owns and operates about 71,600 circuit kilometers of transmission lines at 800/765 kV, 400 kV, 220 kV & 132 kV EHVAC & +500 kV HVDC levels and 122 sub-stations with transformation capacity of about 81,200 MVA.

About 45% of total power generated in the country is wheeled through this transmission network.

Recognizing the role of POWERGRID in the overall development of transmission and power sector, Govt. of India has conferred NAVRATNA upon status to POWERGRID in May` 08.

POWERGRID has continuously meet the challenging targets set under Memorandum of Understanding (MoU) with Ministry of Power.

AWARDS & ACHIEVEMENTS Memorandum of undertaking rating of the Company has consistently been in the highest bracket (“Excellent”) since signing of its first MoU with Ministry of Power in 1993-94.

“MoU Excellence Award” for year 2006-07 for being amongst the top ten PSUs. (past six occasions continuously since 2003-04).

Three National Awards for meritorious performance (for system availability and early completion of project for the year 2007-08).

All India Organization of Employers Industrial Relations award 2007-08.

IEEMA Power Awards 2009 for “Excellence in Power Transmission”. “The First DSIJ Awards 2009”

CERTIFICATES

PAS 99:2006 Integrated Management System (IMS)

ISO 9001:2008 (Quality)

ISO 14001:2004 (Environment)

OHSAS 18001:2007 (Occupational Health & Safety Management System)

SA 8000:2008 (Social Accountability Standard , Quality mgt.)

Transmission /Sub-Transmission Projects

Assignment of a 200km long 220kV line in Afghanistan commissioned in Jan` 2009 .

Consultancy assignments in Afghanistan, Nepal, Bhutan, Nigeria and Dubai .

The implementing agency for 230kV transmission project in Myanmar .

A proposed under-sea interconnection with Sri Lanka .

RESEARCH & DEVELOPMENT ACTIVITIES

Upgradation of transmission lines :Use of Thyristor Controlled Series Compensation :High temperature endurance conductors :Development of pole type tower structure for 400 KV transmission lines.

Transmission highways using higher transmission voltage levels, i.e. 765 kV EHV AC and ±500 kV HVDC .

Development of high capacity ±800kV, 6000MW HVDC transmission system and 1200kV Ultra High Voltage (UHVAC) super grid.

MISSION The mission of the corporation is establishment and operation of regional and national power grids to facilitate transfer of electric power within and across the regions with reliability, security and economy, on sound commercial principles.

POWERGRID is committed to:

a)establish and maintain an efficient and effective "national grid " with due regard to time, cost, technology, and value additions.

b)sustainable development through conservation of natural resources and adopting environment friendly technology on principle of avoidance, minimization and mitigation.

c)ensure safe, occupational hazard free and healthy work environment, to the satisfaction of stake holders in all areas of its activities and shall endeavor to continually improve its management systems and practices in conformity to legal and regulatory provisions.

PART- A

SWITCHYARD PROTECTION

SINGLE LINE DIAGRAM

CIRCUIT BREAKERS A Circuit breaker is an automatically operated electrical switch designed to protect an electrical circuit from damage caused by overload or short circuit. Its basic function is to detect a fault condition and, by interrupting continuity, to immediately discontinue electrical flow.

All circuit breakers have common features in their operation, although details vary substantially depending on the voltage class, current rating and type of the circuit breaker.

Once a fault is detected, contacts within the circuit breaker must open to interrupt the circuit.

Small circuit breakers may be manually operated; larger units have solenoids to trip the mechanism, and electric motors to restore energy to the springs.

Different techniques are used to extinguish the arc : Lengthening / deflection of the arc : Intensive cooling (in jet chambers) : Division into partial arcs : Zero point quenching : Connecting capacitors in parallel with contacts in DC circuits

High-voltage breakers are broadly classified by the medium used to extinguish the arc

•Bulk oil•Minimum oil•Air blast•Vacuum•SF6

LIGHTNING ARRESTOR

A lightning arrester is a device used on electrical power systems to protect the insulation on the system from the damaging effect of lightning.

Metal oxide varistors (MOVs) have been used for power system protection since the mid 1970s.

The typical lightning arrester also known as surge arrester has a high voltage terminal and a ground terminal.

Current from the surge is diverted around the protected insulation in most cases to earth.

PICTURES OF SURGE DIVERTER (LIGHTNING ARRESTOR)

ISOLATOR

• Disconnector or Isolator switch is used to make sure that an electrical circuit can be completely de-energised for service or maintenance.

• Isolator is an off-load device.

CVT

Capacitor Voltage Transformer (CVT), Capacitance Coupled Voltage Transformer(CCVT)

o To step down extra high voltage signals and provide a low voltage .o For measurement or to operate a protective relay.

REACTORS

There are several types of reactors used in power system.

current limiting reactor reactor in neutral to earth connection shunt reactor reactor in harmonic filters smoothing reactor in hvdc systems.

OTHER SWITCHYARD EQUIPMENTS

. BUS BAR

. EARTHING SWITCH

. CURRENT TRANSFORMER

. SHUNT CAPACITANCE

. SERIES CAPACITOR

. MARSHALLING KIOSKS

. STATION EARTHING SYSTEM

. NEUTRAL GROUNDING EQUIPMENTS

. POWER CABLES

. CONTROL CABLES

. INSULATORS

POWER LINE CARRIER COMMUNICATION

PART-B

PLCC is mainly used for telecommunication, tele-protection and tele-monitoring between electrical substations through power lines at high voltages, such as 110 kv, 220 kv, 400 kv.

System the communication is established through the power line.

The audio frequency is carried by a carrier frequency and the range of carrier frequency is from 50 kHz to 500 kHz. The

The voice signal is converted/compressed into the 300 Hz to 4000 Hz range.

It is known as :- Power line Digital Subscriber Line (PDSL) mains communication power line telecom (PLT) power line networking (PLN) Broadband over Power Lines (BPL)

LINE TRAP (WAVE TRAP)

Connected in series with the power (transmission) line.

It blocks the high frequency carrier waves (24 KHz to 500 KHz) and let power waves (50 Hz - 60 Hz) to pass through.

It is basically an inductor of rating in Milli henry (approx 1 milli Henry for 220 KV 1250 Amp.).

It has three main components:-

1. Main coil. 2. Tuning Device. 3. Lightning Arrestor.

PART-C

APPLICATION OF SCADA IN POWER GRID

WHAT IS SCADA ?

• SCADA stands for Supervisory Control And Data Acquisition.

• It is not a full control system, but rather focuses on the supervisory level.

• It is a purely software package that is positioned on top of hardware to which it is interfaced. ( via Programmable Logic Controllers(PLCs)) .

ARCHITECTURE AND FUNCTIONALITY

:: SCADA systems are indispensable in the operation and control of interconnected Power systems.

:: SCADA requires two-way communication channels between the Master Control Centre and Remote Control Centre.

The SCADA systems are arranged to perform the following tasks. • Data Collection (Data Acquisition) • Data transmission (telemetry) • Scanning, Indication, Monitoring, Logging. • Control and indication. • Ensure sequential events. • Data presentation, display, reporting • Execution of operating, commands: on/off,raise/lower. • Network supervision, alarms and report any uncommon change of state.

SCADA

Communication channel

ARCHITECTURE OF SCADA

SCADA AUTOMATION FOR SUBSTATION

1.Alarm function

2.control & indication 3.data collection, recording, display 4.protective functions 5.monitoring & control 6.operation of devices with predetermined time

BIBLIOGRAPHY

• SWITCHGEAR AND PROTECTION RAO S.S• POWER SYSTEM ENGINEERING WADHWA C.L• POWER SYSTEM ANALYSIS KOTHARI ,NAGRAT• POWER SYSTEM PROTECTION RAO T.S.M• FUNDAMENTALS OF PWER SYSTEM PROTECT BHIDE S.R.• POWER SYSTEM PROTECTION AND SWITCHGEAR RAVINDRANATH B.

INTERNET SOURCES:•WWW.POWERGRIDINDIA.COM•http://en.wikipedia.org/wiki/Powerline_communication

THANK YOU