CHALLENGES IN INTEGRATING SR WITH NEW GRID V.S.Verma Member(CERC )

Indian Power System : Amongst the Largest in the World 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 WESTERNRE GION EASTERN REGION NORTHERN REGION NORTH- EASTERN REGION 1 2 TWO ELECTRICAL REGIONS w.e.f Aug ‘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

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 MW (28.4 % of India) IC – DM – 8549 DC – 185 IC – DM – DC – 265 DC – 239 DC – 63 DM – DM – 3348 IC – 2457 IC – IC – Installed Capacity in MW DM – Max Demand Met in MW DC – Max Daily Consumption in MU Consumer Profile Domestic Commercial Industrial Irrigation Others SR IC – DM – DC – 725 Pondy DM – 320 DC – 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 22 nd Sep 1991 Trial synch operation between 8-14 Oct 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 profile  More reserves for System Operator Issues  Line loading issues in WR  Communication and co-ordination issues  Visibility issues due to limited telemetry  No firm commercial arrangements in place  Robust 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 SR Typical 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

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

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 bottlenecks A 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:  Tamilnadu MW  Andhra Pradesh MW  Karntaka MW  Kerala MW  Tamilnadu MW  Andhra Pradesh MW  Karntaka MW  Kerala MW Installed Capacity of WIND in SR as on 31 st 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 at 00:42 Hrs TN MET NEARLY 40% OF DEMAND THROUGH WIND

WIND GENERATION OF KARNATAKA FROM TO

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 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 SOMANAHALLI KALAVINDAPATTU 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 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-2012 U#2-March-2013 Vallur TPS (3x500MW) U1-Aug-12, U2-Feb-13,U3-Sep-13) Mettur Stage-3 TPS (600MW) First Sync. Done On 4 th may 2012 Vijayawada Nellore Tiruvalam Somanahalli Hosur Salem Nellore pooling station Gooty N’Sagar Karnool Raichur 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 done U2-1x150 MW-June-12) North Chennai TPS (2x600MW) Meenakshi U1-1x150MW –June 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)