CHALLENGES IN INTEGRATING SR WITH NEW GRID

V.S.VermaMember(CERC)

Indian Power System :

Amongst the Largest in the WorldAmongst the Largest in the World

Spread over 3200 kms from North to South & 2900 kms from East-West

Spread over 3200 kms from North to South & 2900 kms from East-West

Some Typical Numbers … Region = 5

States & UT = 28 State, 7 UT

Installed Capacity > 201 GW

Substation = 3000 ( upto 132kV)

Generating Stations = 657 Nos.( 1257 Gen. units)

Trans. Line = 9350 ( upto 132kV)

Transformers = 2262 Nos.

Voltages = 132kV, 220kV, 400kV,

500kV (HVDC), 765kV,

800kV (HVDC), 1200kV

SOUTHERN REGION

WESTERNREGION

EASTERN REGION

NORTHERN REGION

NORTH-EASTERN REGION

1

2

TWO ELECTRICAL REGIONS w.e.f Aug. 2006

‘NEW’ GRID

HVDC INTERCONNECTS

AC INTERCONNECTS

MAJOR INTERCONNECTIONS

2X500 MW BACK TO BACK STATION AT

GAZUWAKA(SR)

1000 MW BACK TO BACK STATION AT

BHADRAWATI(WR)

TALCHER

KOLAR

TALCHER-II TO KOLAR

2000 MW BIPOLE LINK

www.srldc.org SRLDC

Southern Grid Over View

651(‘000 Sq KM) (19 % of India)

Population 22.5 Crores (22% of India)

Sea Coast Around 4000 KM

I C 53322 MW (28.4 % of India)

IC – 11102

DM – 8549DC – 185

IC – 12922DM – 11972DC – 265

DC – 239

DC – 63

DM – 10856

DM – 3348

IC – 2457

IC – 16021

IC – Installed Capacity in MW

DM – Max Demand Met in MW

DC – Max Daily Consumption in MU

22%

6%

34%

31%

6%

Andhra Pradesh

Consumer Profile

Domestic

CommercialIndustrial

Irrigation

Others

21%

5%

34%

35%

5%

Karnataka

49%

18%

27%

2% 4%

Kerala

25%

10%

38%

20%

7%

Tamil Nadu

SR

IC – 53322DM – 33037DC – 725

Pondy

DM – 320DC – 6.97

SR-WR Synchronisation: A little history 400 kV Ramagundam-Chandrapur line

commissioned in Nov 1990 Radial assistance to SR during April-

May1991 Trial Synchronisation 22nd Sep 1991 Trial synch operation between 8-14 Oct

1991- 150 Hrs- 55 MUs from SR to WR and 0.5 MU from WR to SR

WR was connected to NR through HVDC during that time

SR-WR Synchronisation: A little history Advantages

Frequency stability due to larger inertia of combined grid

Better voltage profileMore reserves for System Operator

IssuesLine loading issues in WRCommunication and co-ordination issuesVisibility issues due to limited telemetryNo firm commercial arrangements in placeRobust 400 kV backbone not in place

SR-NEW Grid Synchronisation: Watch list Load –Generation mismatch and impact on regional line

flows. Seasonal and over-the-day Frequency profile- Behavioral aspects of both Grids- Load

changeovers, pump operation etc Congestion issues in each Grid Co-ordination of defense plans, Special Protection

Schemes deployment. Frequency Response Wide area Visualisation tools- PMU and Applications Integration of Renewables Impact on Transfer Capability

Need for a strong backbone network spanning all Regional Grids

SHORTAGES IN NEW AND SR GRID

Shortages dictate the flow direction on synchronisation. SR would be deficit Region in the near future as planned generation(UMPP, Koodankulam,IPPs) have not materialized. Shortages in SR has shown an increasing trend in the past few years

MISMATCH IN LOAD PATTERN SR, ER and WR peak in March NR typically peaks between June to

August Hydro and Wind generation peaks during

June-October in SR

Dec-June pattern

Jul-Nov pattern

Shortages in NEW and SRTypical day March 15, 2012

SR

NEW

NR, 2112 MW, 40 MU

WR, 5017 MW, 90 MU

ER, 675 MW, 9 MU

NER, 116 MW, 2 MU

7158 MW, 136 MU

Typical day July 15, 2011

NR, 1200 MW, 20 MU

WR, 4375 MW, 58 MU

ER, 975 MW, 12 MU

NER, 283 MW, 2 MU

1950 MW, 36.5 MU

Peak shortage in MW of all regions

0

5000

10000

15000

20000

25000

2003-04 2004-05 2005-06 2006-07 2007-08 2008-09 2009-10 2010-11 2011-12

MW

NR

WR

SR

ER

NER

TOTAL

Shortage in MU of NEW Grid and SR Grid

0

10000

20000

30000

40000

50000

60000

70000

80000

2003-04 2004-05 2005-06 2006-07 2007-08 2008-09 2009-10 2010-11 2011-12

MU NEW GRID

SR

SHORTAGES IN SR SHOW AND INCREASING TREND WHEREAS NEW GRID SHORTAGES SHOW A DECREASING TREND. ON SYNCH FLOW WOULD BE PREDOMINANTLY TOWARDS SR:- NEED FOR A STRONG BACKBONE

FREQUENCY PROFILE NEW AND SR GRID

Frequency profile is another indicator of the Load Generation balance and behaviour of each system. Larger the frequency difference across a seam, more power can be expected to flow.

Frequency Profile NEW and SR 2001-12MAXIMUM, MINIMUM & AVERAGE FREQUENCY PLOT FROM APRIL-01 ONWARDS(Southern Region)

47.5

48.0

48.5

49.0

49.5

50.0

50.5

51.0

51.5A

pr-

01

Ap

r-0

2

Ap

r-0

3

Ma

r-0

4

Ma

r-0

5

Ma

r-0

6

Ma

r-0

7

Ma

r-0

8

Ma

r-0

9

Ma

r-1

0

Ma

r-1

1

Ma

r-1

2

DAY ---->

FR

EQ

UE

NC

Y I

N H

Z -

-->

MAXIMUM MINIMUM AVERAGE

47

48

49

50

51

52

53

54

Date -->

Hz -

->

MAXIMUM MINIMUM

Frequency profile of NEW Grid

0

10

20

30

40

50

60

70

80

90

1001-

Apr-

2009

21-M

ay-2

009

10-J

ul-2

009

29-A

ug-2

009

18-O

ct-2

009

7-D

ec-2

009

26-J

an-2

010

17-M

ar-2

010

6-M

ay-2

010

25-J

un-2

010

14-A

ug-2

010

3-O

ct-2

010

22-N

ov-2

010

11-J

an-2

011

2-M

ar-2

011

21-A

pr-2

011

10-J

un-2

011

30-J

ul-2

011

18-S

ep-2

011

7-N

ov-2

011

27-D

ec-2

011

15-F

eb-2

012

5-Ap

r-20

12

% o

f tim

e <4

9.2

Hz

48.00

48.50

49.00

49.50

50.00

50.50

51.00

Min

Fre

quen

cy d

urin

g th

e da

y

% of time

Min freq

Frequency profile of SR Grid

0

10

20

30

40

50

60

701-

Apr-

2009

21-M

ay-2

009

10-J

ul-2

009

29-A

ug-2

009

18-O

ct-2

009

7-D

ec-2

009

26-J

an-2

010

17-M

ar-2

010

6-M

ay-2

010

25-J

un-2

010

14-A

ug-2

010

3-O

ct-2

010

22-N

ov-2

010

11-J

an-2

011

2-M

ar-2

011

21-A

pr-2

011

10-J

un-2

011

30-J

ul-2

011

18-S

ep-2

011

7-N

ov-2

011

27-D

ec-2

011

15-F

eb-2

012

5-Ap

r-20

12

% o

f Tim

e <4

9.2

Hz

48.00

48.50

49.00

49.50

50.00

50.50

51.00

Min

Fre

quen

cy d

urin

g th

e da

y

% of time

Min freq

Day wise Minimum Frequency profile of SR and NEW Grid

48.00

48.20

48.40

48.60

48.80

49.00

49.20

49.40

49.60

49.80

50.00

1-Ap

r-20

09

21-M

ay-2

009

10-Ju

l-200

9

29-A

ug-2

009

18-O

ct-2

009

7-De

c-20

09

26-Ja

n-20

10

17-M

ar-2

010

6-M

ay-2

010

25-Ju

n-20

10

14-A

ug-2

010

3-Oc

t-20

10

22-N

ov-2

010

11-Ja

n-20

11

2-M

ar-2

011

21-A

pr-2

011

10-Ju

n-20

11

30-Ju

l-201

1

18-S

ep-2

011

7-No

v-20

11

27-D

ec-2

011

15-F

eb-2

012

5-Ap

r-20

12

% o

f Tim

e <4

9.2

Hz

NEW grid

Day wise Minimum Frequency profile of SR and NEW Grid

48.00

48.20

48.40

48.60

48.80

49.00

49.20

49.40

49.60

49.80

50.00

1-Ap

r-20

09

21-M

ay-2

009

10-Ju

l-200

9

29-A

ug-2

009

18-O

ct-2

009

7-De

c-20

09

26-Ja

n-20

10

17-M

ar-2

010

6-M

ay-2

010

25-Ju

n-20

10

14-A

ug-2

010

3-Oc

t-20

10

22-N

ov-2

010

11-Ja

n-20

11

2-M

ar-2

011

21-A

pr-2

011

10-Ju

n-20

11

30-Ju

l-201

1

18-S

ep-2

011

7-No

v-20

11

27-D

ec-2

011

15-F

eb-2

012

5-Ap

r-20

12

% o

f Tim

e <4

9.2

Hz

NEW grid

RAPID GROWTH IN RENEWABLES

The growth of wind and solar would be very high in South. This would add to the uncertainity as well as Transmission requirement. High wind often co-incides with high hydro generation in SR which may cause bottlenecksA strong transmission backbone would be a necessity to accommodate these levels of uncertainity and co-incidental generation

GROWTH IN INSTALLED CAPACITY OF WIND IN SR

Source:http://www.inwea.org/

Tamilnadu - 6953.09 MW Andhra Pradesh - 189.74 MW Karntaka - 1726.95 MW Kerala - 34.8 MW

Tamilnadu - 6953.09 MW Andhra Pradesh - 189.74 MW Karntaka - 1726.95 MW Kerala - 34.8 MW

Installed Capacity of WIND in SR as on 31st March 2012:HIGH GROWTH IN RENEWABLES IN SR EXPECTED IN THE FUTURE ALSO. THIS ADDS TO THE UNCERTAINITY IN LOAD GENERATION BALANCE AND INCREASES THE NEED FOR RESERVES.

WIND GENERATION OF TAMILNADU

Peak of Wind generation in Tamilnadu touched 3820 MW on 30.05.2012 at 00:42 HrsTN MET NEARLY 40% OF DEMAND THROUGH WIND

WIND GENERATION OF KARNATAKA FROM 27.05.2012 TO 30.05.2012

CO-ORDINATION OF DEFENSE PLANS

Defense plans in each grid needs to be co-ordinated to act synergistically. For example, consider a large outage in SR and consequential frequency dip. If UFR throws off load in NEW Grid, the problem could worsen dramatically.SPS, Islanding schemes may have to be deployed to contain cascade trippings as the entire country would be in one grid

Grid Defense Plans: Settings

ALL DEFENCE PLANS IN REGIONS HAVE TO BE CO-ORDINATED

AUFR settings :Stage-I Stage-II Stage-III

NR 48.8 Hz 48.6 Hz 48.2 HzWR 48.8 Hz 48.6 Hz 48.2 HzER 48.5 Hz 48.2 Hz 48.0 Hz

NER 48.8 Hz 48.5 Hz 48.2 HzSR 48.8 Hz 48.5 Hz 48.2 Hz

ER CONSTITUENTS HAVE ALSO AGREED TO BRING UP THE SETTINGS

Special Protection Schemes in SR

Commissioned

Proposed. Yet to be Commissioned

To be proposed

• VOLTAGES:- Pockets of extreme high(Vemagiri complex) and low(Chennai and Bangalore) voltages needs to be addressed immediately or they may constrain import/export capability

• VISUALISATION:- The Operator would now be exposed to a larger Grid and more incidental network flows. Advance technology like PMU with its applications need to be in place.

• PLANNING: Better planning/forecasting by each control area (esp. of RE Generation) – dependence on UI to be minimised

Typical flow directions in SR

NARENDRA

MAHABOOB NAGAR

CHITTOOR

VIJAYAWADA

GAZUWAKA

GHANAPUR

RAICHUR

GOOTY

SALEM

UDUMALPET

TRICHUR

MADURAI

TRICHY

SRIPERUMBUDUR

NEYVELI

GUTTUR

KAIGA

RSTPP

BHADRAVATI

MUNIRABAD

P

P

P

P

P

KOLAR

TALCHER

JEYPORE

HOSUR

SSLMM

MMDP

TRIVANDRUM

NELLORE

KALPAKKA

SIMHADRI

HIRIYUR

TALGUPPA

KADAPA

NEYVELI TPS – 1 (EXP)

HOODY

KURNOOL

KHAMMAM

N’SAGAR

ALMATHY

MYSORE

NELAMANGALA

SOMANAHALLIKALAVINDAPATTU

TIRUNELVELI

DITCHIPALLY

PUGALUR

GAJWEL

BTPS

WARANGAL

Highly loaded

Medium loaded

Lightly loaded

VOLTAGE CONSTRAINTS

LINE LOADING / ANGULAR

CONSTRAINTS

LINE LOADING CONSTRAINTS EVACUATION

CONSTRAINTS

The road ahead

765 kV Interconnects between SR-NEW Grids would be in place by early 2014. With the 765 kV backbone network in place in SR and the high power corridor spanning WR-ER-NR, the network would be robustly tied.

Kudankulam Nuclear TPS(2x1000MW)-U1-Nov-12

U2-6months after Unit1

Neyveli TS2 Exp(2x250MW)U#1- Dec-2012U#2-March-2013

Vallur TPS(3x500MW)U1-Aug-12, U2-Feb-13,U3-Sep-13)

Mettur Stage-3 TPS(600MW)First Sync. Done On 4th may 2012

Vijayawada

Nellore

TiruvalamSomanahalli

Hosur

Salem

Nellore pooling stationGooty

N’Sagar

KarnoolRaichur

Sholapur

Madugiri

Vemagiri Pooling station

Khammam

Hyderabad

Warda

TPCIL

Planned Transmission system to relieve congestion in SR

Major Generation to be expected near Future

Simhapuri (U1-1x150MW –COD doneU2-1x150 MW-June-12)

North Chennai TPS(2x600MW)

MeenakshiU1-1x150MW –June-12

765 kV Backbone

network in SR

PAN INDIA PMU SPREAD ( 53 PMUs)

AFTER COMPLETION OF ALL PILOT PROJECTS

In addition, the URTDSM project of POWERGRID would

add another 1186 PMUs to the system)