New Technologies in

Transmission

MANJU GUPTA

POWERGRID

May 1, 2012

Issues in Transmission Development

• Right-of-Way (ROW)

Environmental

Wild life sanctuary

Urban areas

• Coordinated development of cost effective Tr.

corridor

• Flexibility in upgradation of transfer capacity

matching with power transfer requirement

• Long distances between Resource Rich areas and

Load centres

Issues in Transmission Development

• Optimisation of investment

• Resettlement and Rehabilitation

• Non-discriminatory open access

Market driven exchanges may influence pattern of power flow

Periodic review and strengthening

Necessitates optimal utilization of existingtransmission infrastructure by enhancingtransmission capacity using emerging technologiesat marginal investment

Technology Integration

To ensure development of Power System in

an optimal manner –

• Enhance the capacity of existing system –

Tr. asset management- using emerging technologies at marginal investment to

get optimal transmission cost

• Technology for new system keeping in view

long-term perspective

To fulfill above objectives, focus in all stages of

Transmission system need to be given

– Planning stage

– Design stage

– Construction stage

– Operation and Maintenance (O&M) stage

– Grid Management stage

Technology Application

High Intensity (MW/m) transmission corridor by increasing

Voltage level

Current order

Both Voltage & Current

Regulation of Power flow by

HVDC

Hybrid AC & HVDC

Flexible AC Transmission devices

Technology Integration at Planning Stage

Road Map for Indian Power System

High Power Intensity Corridor

RoW

(m)

Capacity

(MW)

MW/m

RoW

400kV S/c 52 500 9.6

400kV D/c 46 1000 21.8

765kV S/c 64 2500 39

765kV D/c 69 4000 58

800kV DC 70 6000 85

64 m230 m

1977 1990 2000 2012 2017-18

Voltage

(kV)

Year

220kV400kV

500kV

HVDC

765kV

800kV

HVDC

Increase in Transmission voltage

Complexities with high voltage AC system

• Reactive Power Management

• Availability of switchgear

• Corona Loss

• Sustainability of grid during contingencies

Voltage Upgradation

1200kV

Technology Integration at Planning Stage..contd

Increase in Current Order

Multi Conductor Bundle Line

400kV, 800kV, 1200 kV AC etc.

High Temperature Low Sag (HTLS) Conductor

ACSS (Aluminium Conductor Steel Supported)

ACAR (Aluminium Conductor Alloy Reinforced)

Invar conductor

Gap type conductor

High Surge Impedance Loading Line(HSIL)

Emerging Technology at Design Stage

Transmission line

Tower Structure - Compact / Pole type structure

Reduction in land use by Pole type tower as compared to lattice type

400 kV 220 kV

• Lattice Tower * 9.0 m 6.0 m

• Pole Structure * 1.85 m 1.4 m

* Base width at ground level

Emerging Technology at Design Stage – Substation

Equipment

Space reduction – Compact substation, SAS (S/s

Automation System) having standard communication

models which have inter operability of control &

protection devices

Area : 30-35 Acres Area : 6-8 Acres

Air Insulated S/s (AIS) Gas Insulated S/s (GIS)

Mobile Sub-stations

For faster restoration of supply

Restoration time - 10 to 15 days.

In- Principle acceptance from CERC & Beneficiaries

Aerial Patrolling of Transmission Lines

Ministry of Defense/ DGCA are approached

Use of Unmanned Aerial Vehicle (UAV) is also being explored

National Transmission Management Centre

Remote Operation and control of Trans. Elements / Unmanned

substations.

To enhance Grid reliability while improving Asset Productivity

Reduction in down time

Availability of Experts round the clock

On Line Transformer Monitoring

For prediction of fault in advance

O&M – Upcoming Technology

High Voltage line

Increase the capacity of trans. corridor through HSIL/re-

conductoring with HTLS /Upgradation

Utilisation of transmission lines upto full thermal capacity –

Series capacitors, SVC, FACTS

Optimization of Tower design – tall tower, multi-ckt. tower

GIS substation

EHVAC : 400kV 765kV 1200kV

HVDC : 500kV 800kV

Technology being Adopted

765 KV SUBSTATION AT

SEONI

765 KV SUBSTATION AT SEONI

765 KV SUBSTATION AT SEONI

Impact of Series Capacitor on

Transmission capability

Series Capacitor installation at Raipur

• Combination of FC or

TSC + TCR

• Stabilize voltage in the

systems and controls

overvoltages

• Reduces transmission

losses

Static Var Compensator(SVC)

•

Static Var Compensator(SVC)

• 2 nos. + 140MVAR SVCs

in operation at 400/220kV

Kanpur S/s

•SVCs to be implemented

• +600 / -400 MVAR at

Ludhiana

• +400/ -300 MVAR at

Kankroli

• +300 / -200 MVAR at

New Wampoh

ROW = 85 Mts ROW = 64 Mts

Pole Type TowersPole Type Tower

21

DOUBLE CIRCUIT TOWER MULTI CIRCUIT TOWER

(45 m. High) (70 m. High)

Multi-conductor Bundle line

220 KV S/C Chukha-Birpara line

upgraded with 400/220 KV multi-

circuit line in Jaldapara

Sanctuary without felling of

single tree

220 KV S/C Chukha-Birpara line

upgraded with 400/220 kV multi-circuit

line in Jaldapara Sanctuary without

felling of single tree

72.5

me

tres

75.0

metr

es

Protection of Wild LifeSpecially

designed

high - rise

towers

(75m) to

reduce tree

cutting

(Reduced

from 90000

to 14739 in

Rajaji

National

Park)

Application

of Multi ckt

and Compact

towers to

reduce

corridor

requirement

9 - 25 mtr

50 mtr

4 - 5 mtr approx

Multi-ckt Tower

HVDC Tower

Green Substation

GIS S/s

Hybrid Switchgear

800 kV, 6,000 MW HVDC

1200kV UHVAC

High Temperature Low Sag

(HTLS) Conductor lines

High Surge Impedance Loading

Line

Mobile Substation

Superconductor

Pioneering Efforts

+/- 800 KV HVDC TRANSMISSION LINE

TOWER

B Type Tower

Establishment of 1200kV UHVAC Test Station at Bina

in association with 33 domestic manufacturers

– For indigenous development of 1200KV technology

– Indigenous development of equipments shall help in

• To conduct developmental tests to optimize design of

substation and transmission equipments.

• Indigenous development shall help in reduction of cost and

convenience of O&M

1200 kV National Test Station

38

Satna line

400kV Bina Bus

To 400kV Satna line

1200kV line1200/400kV Transformer

1200/400kV Transformer

400kV line400kV line

Test Station Configuration

1200kV Transformer successfully developed, tested and commissioned.

Test Setup for 1200kV Transformer 1200kV Transformer successfully tested

1200 kV Transformer successfully Developed, Tested and Commissioned

1200kV CVT and LA

72.5 m55m 125 m

Qutab Minar S/C Tower –A type D/C Tower

1200 kV Tower

1200kV Test Station

44

1200kV Test Station

1200kV Gantry Structure

46

A type 55 m

D type

1200kV Towers- S/c

47

Fig: 1200kV bushing mounted on BHEL

transformer at Bina 1200kV National Test Station

Fig: 1200kV BHEL Transformer with cooler assembly fitted

1200kV Transformer

48

1200kV CVT

The initial operational experience of 1200kV Test

Station will prove to be the cornerstone of future

commercial projects

The results and feedback of the various field tests/

trials carried out at 1200kV National Test Station

shall be useful for developing field proven

equipment of 1200KV system in India

India’s first 1200 kV UHVAC Transmission Line

from Wardha to Aurangabad is already under

construction

1200kV Test Station

1200kV Transmission Corridor

• It’s India’s first 1200 kV UHVAC Transmission Line –

400kV Double circuit line upgradable to 1200kV

• Towers and Foundations are designed considering

1200kV parameters

• Tower designs are suitable for operation of two

circuits of 400kV

• Earth-wire to be provided considering 1200kV

• Line insulation to be initially provided for 400kV

• Bunching of conductor bundle along with change of

insulator string to be carried out when upgrading to

1200kV51

1200kV Wardha-Aurangabad Line

52

Nominal Voltage 1150 kV

Highest voltage 1200 kV

Surge Impedance Loading (SIL) 6030 MW

LIWL 2400- Switchgear

SIWL 1800 kV-Switchgear

CFO 1913 kV peak

One min. Power Freq withstand 1200 kV

Electric field at ROW* 4.0 kV/m (criteria less than

5kV/m)

ROW 90 m

1200kV Wardha-Aurangabad Line

• .

53

CONDUCTOR BUNDLE

Conductor-Bundle Octagonal ACSR Moose

ELECTRICAL CLEARANCES

Power Frequency live-metal clearance 2.4 m

Switching Surge Clearance (1.75 p.u.) 8 m

Phase to Phase Switching 24m

Ground Clearance 24m (10kV/m electric

field limit)

1200kV Wardha-Aurangabad Line

400 kV D/C Up-gradable

to 1200 kV AC Tower Configuration

Insulation Level Comparison

5.25

4.15

3.22

2.45

3.06

2.37

1.84

0

1

2

3

4

5

6

245 420 800 1200

System Voltage (kV)

P.U

. LIWL

SIWL

• Handling very huge amount of Power

transfer (6000-8000MW)

• Reactive Power management

• Large size of equipments

• Transport Limitations

• Cost Optimization

Due to the above factors, reduced Insulation Level (margin)

has been adopted for 1200kV system

Challenges in 1200kV Transmission

-3000

-2000

-1000

0

1000

2000

3000

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500 7000 7500 8000

Power Flow (MW)

Re

ca

tiv

e F

low

( M

VA

R)

Reactive Power Characteritics-1200kV Line

Wardha-Aurangabad Line

High Surge Impedance Loading Line(HSIL)

0.457 m

0.457 m

1.1 m

0.9 m

Symmetrical bundle spacing Non-symmetrical bundle spacing

Surge Impedance = 270-300 ohm Surge Impedance = 200-210 ohm

Expanded Conductor Bundle

Sub-conductor

Spacing

457 mm 1000 mm

XL (ohms/km) 0.16178 0.14322

XC (Mohms-km) 0.11032 0.09361

SI (ohms) 134 116

SIL (MW) 1198 1382

Increase in SIL with Sub-conductor Spacing for 400

KV D/C (QUAD MOOSE) LINE

Substation Equipment for

Disaster Management

… ERS-Substation

Snapshots : ERS S/S

ERS S/S - unloading from Aircraft

ERS S/S under transportation

ERS-Substation - Need

POWERGRID has played a vital role in quick restoration

of power supplies across the country by extensive use of

ERS for Transmission Lines. However, there is no quick

restoration means in S/S to cater to an emergency situation.

ERS-S/S readily fills this gap by providing a technological

solution to address the need for:

Disasters damaging S/S

Transformer Failure

Planned transformer outages for internal Inspection

Additional Usage of ERS-S/S

Terrorist attacks & Sabotage

Temporary increase in S/S Capacity

Alternative arrangement in case of delay in S/S commissioning

Address sudden spurt in secure load requirement viz., National Events like Commonwealth games etc.

Superconducting Transmission

Proposal:

“To lay down experimental Super conducting AC

line at 220 kV voltage level to study the feasibility

of Technology in India”

Objective:• To install and operate a superconducting cable

system under realistic conditions in the grid.

• Assessing the performance by carrying out

suitable tests

• Exploring possible application areas

Project Schematic

Indian Power System is characterized by

Large generation addition on continuous basis

Continuous expansion of grid through increasing grid connectivity -

leading to spread of the grid geographically

Power flow in multi direction

Wide variation in generation as well as demand on daily/seasonal

basis

Open Access and frequency linked Unscheduled Interchange (UI)

mechanism in place

Continuous demand for digital grade power and economic dispatch.

Features of Indian Power System

With the above growing aspects in view, it is important to know the

dynamic state of grid in terms of –

Angular and Voltage stability

How much increase in transfer capacity can take place at different instances on

various transmission elements

Control & regulation of power flow to maintain grid parameters

Remedial Action Scheme(RAS) and System Integrated Protection

Scheme(SIPS) for

– In the event of severe contingency occurs/likely to occur which may lead

to grid disturbances, identify what corrective actions to be taken and its

implementation

Above aspects call for development of Smart Grid comprising Wide Area

Measurements (WAM) using Phasor Measurement Unit(PMU), Adaptive

Islanding, Self-healing aspects. This shall facilitate safety, security and

reliability in operation of large & geographically spread grid

Need for Smart Grid

For this, there is a need to develop of intelligent Grid

with State-of-the-Art features like-

– Phasor Measurement Technique

– Wide Area Measurement (WAM)

– Adoptive Islanding

– Self healing Grids

– Probabilistic Assessment, Dynamic Stability Assessment and

Voltage Stability Assessment (VSA) technique etc.

Smart Grid …contd