GRID OPERATION AND UTILITY OF MODERN LOAD DISPATCH AND COMMUNICATION SYSTEMS

GRID OPERATION GRID OPERATION

ANDAND

UTILITY OF MODERN LOAD DISPATCH UTILITY OF MODERN LOAD DISPATCH

AND AND

COMMUNICATION SYSTEMSCOMMUNICATION SYSTEMS

ALOK ROYALOK ROYGeneral ManagerGeneral Manager

Northern Regional Load Dispatch CenterNorthern Regional Load Dispatch Center

Indian Power Grid – its Evolution• Phenomenal expansion since Independence (1947)

Generation : 1349 MW 105,800 MW (in 1947) (in 2003)

Grid :

Local grid – at the time of Independence.

State Grids – emerged in 1960s.

Regional Grids – in 1970s.

Five Regional Grids – Northern, Western, Southern,

Eastern & North-eastern

National Grid – All Five Regions Interconnected (2002)

State Govt.

SERC

IPPs SGC CPPs

STU

SLDC

Distn Cos.

Consumers

Central Govt.

CERC

CGC Imports

CTU

RLDC

REB

CEA

• IEGC operates on states periphery

• Complementary to Availability Tariff

• Endeavour to maintain frequency in the 49.0 – 50.5 Hz range

• Free Governor mode of operation

• Charge for reactive energy - Voltage related

Indian Power System Has PeculiaritiesHence Solutions Are Tailor Made

Departures From Conventional Practices:

- Actual Interchanges would be allowed to deviate from the scheduled interchanges - Frequency linked generation dispatch

- Frequency would be allowed to float

- Frequency linked pricing of deviations from scheduled interchange leading to spot and balancing market solutions - Trading could be in the form of a deviation from scheduled interchange rather than on pre-agreed/scheduled basis

Growth of installed capacity for electricity in India

0

20000

40000

60000

80000

100000

120000

1990

-91

1991

-92

1992

-93

1993

-94

1994

-95

1995

-96

1996

-97

1997

-98

1998

-99

1999

-200

0

2000

-200

1

2001

-200

3

in MW

Fuel wise break-up of installed capacity in power sector

2.60% 1.40% 25%

71%

HydroThermalNuclearWind

Total installed capacity is 105,800 MW

Sector wise consumption of electricity in India

22%

29%

5%

35%

6%

3%

IndustryDomesticRailwaysAgricultureCommercialOthers

Hydro Thermal mix in India

25% 4%

71%

ThermalHydroNuclear+Wind

4850

23000

30000

0

5000

10000

15000

20000

25000

30000

35000

Plan

Cum

ulat

ive

Cap

acity

(MW

)

By 2002 By 2006-07 By 2011- 12

Growth of Cumulative capacity of Inter-regional linksGrowth of Cumulative capacity of Inter-regional links

NORTHERN REGIONNORTHERN REGION

Salient FeaturesNorthern Regional Power System

Largest in geographical area amongst the five regions of India covering 30.7% of the area and approx 29.9% of the country’s

population .

Largest number of participating constituents (9 states, 5 Central generating companies, one Central Transmission Utility and Bhakra BeasManagement Board).

Salient FeaturesNorthern Regional Power System

Effective generation capacity 28794 MWRegional Peak Met 23015 MW

Average Energy Consumption

Thermal (coal fired)54%

Hydro31%

Nuclear4%

Thermal (gas fired)11%

425 MU / day

Central --39.4%, BBMB—9.9%, State—50.3%

Salient FeaturesNorthern Regional Power System

+ 500 kV HVDC 1630 Ckt. Kms.

400 kV 15033 Ckt. Kms.

220 kV 28353 Ckt. Kms.

TOTAL 45016 Ckt. Kms.

Transmission system

Salient FeaturesNorthern Regional Power System

Largest Generating Stations

Thermal (coal fired) SSTPS(NTPC) 2000 MW

Hydro Bhakra Complex (BBMB) 1493 MW

Nuclear RAPS Complex (NPC) 740 MW

Thermal (gas fired) Dadri Gas (NTPC) 829.78 MW

Northern Region Load Curve For 02-11-2003

5000

10000

15000

20000

25000

0:00 3:00 6:00 9:00 12:00 15:00 18:00 21:00

Time

MW

48.00

48.50

49.00

49.50

50.00

50.50

51.00

51.50

52.00

Hz

Load Freq

`

COMMERCIAL MECHANISMCOMMERCIAL MECHANISM

AVAILABILITY BASED TARIFF

(A) CAPACITY CHARGE

(B) ENERGY CHARGE

(C) ADJUSTMENT FOR DEVIATIONS

(U I CHARGE)

(A) = a function of the Ex-Bus MW availability of Power Plant for the day declared before the day starts x SEB’s % share

(B) = MWh for the day as per Ex-Bus drawal schedule for the SEB finalised before the day starts x Energy charge rate

(C) = Σ (Actual energy interchange in a 15 minute time block – scheduled energy interchange for the time block) x UI rate for the time block

TOTAL PAYMENT FOR THE DAY = (A) + (B) ± (C)

ADVANTAGES : (A) AND (B) DO NOT DEPEND ON ACTUAL PLANT

AVAILABILITY AND GENERATION / DRAWAL. ALL DEVIATIONS TAKEN CARE OF BY (C).

NO COMPLICATION REGARDING DEEMED GENERATION.

NO NEED FOR UNANNOUNCED TESTS.

PERPETUAL INCENTIVE FOR MAXIMISING GENERATION AND REDUCING DRAWAL DURING DEFECIT, BUT NO INCENTIVE TO OVER GENERATE DURING SURPLUS.

UNSCHEDULED INTERCHANGES (UI)I.E. DEVIATIONS FROM SCHEDULES

ENCOURAGED IF GOOD FOR THE GRID, DISCOURAGED IF BAD FOR THE GRID, BUT ALLOWED BECAUSE IT ENABLES MEETING MORE DEMAND AND ENHANCES MERRIT-ORDER.

GOOD UI HELPS IN IMPROVING FREQUENCY AND ENABLES ONE CONSTITUENT TO HELP THE OTHER (FOR MEETING MORE CONSUMER DEMAND I.E REDUCING LOAD SHEDDING)

UI PROVIDES THE MECHANISM FOR ON-LINE DISPLACEMENT OF COSTLIER GENERATION BY CHEAPER GENERATION : ULTIMATE OPTIMISATION

MODERNISATION OF MODERNISATION OF POWER SYSTEM OPERATIONPOWER SYSTEM OPERATION

ULDC SCHEMEULDC SCHEME

POWERGRID is implementing ULDC schemes

in all the five regions with state of the art

SCADAEnergy Management System

andDedicated Communication System

UNIFIED LOAD DESPATCH & COMMUNICATION (ULDC)

SCHEMES

ULD & C PROJECT: OBJECTIVESULD & C PROJECT: OBJECTIVES

To haveTo have• Greater and deeper visibility of the power system Greater and deeper visibility of the power system

under controlunder control

• Better communication and co-ordination between Better communication and co-ordination between control centers control centers

• Effective management of grid parameters viz. Effective management of grid parameters viz. frequency, voltage etc. and better grid security frequency, voltage etc. and better grid security through various SCADA/EMS features resulting in through various SCADA/EMS features resulting in betterbetter

Operations schedulingOperations schedulingOperations monitoring and controlOperations monitoring and controlPower system analysisPower system analysis

• A real time environment for dispatcher trainingA real time environment for dispatcher training

HIERARCHICAL SETUP

RTU RTU RTU

SUB LDC SUB LDC SUB LDC

SLDC SLDC SLDC

ERLDC WRLDC NRLDC SRLDC NERLDC5 Nos.

NLDC

32 Nos.

51 Nos.

1160 Nos.

UNIFIED LOAD DESPATCH & COMMUNICATION SCHEME (NORTHERN

REGION)

Chandigarh,BBMB

DVB

Lucknow

Panipat(HSEB)

Patiala

Panipat (BBMB)

Dadri (B)

Dadri (H)

Rishikesh

Bhilwara

Kota

Ratangarh

Narwana

Hamirpur

Laltonkalan

Jallandhar (P)

Jallandhar (B)

Ganguwal (B)

Heerapura

Jammu & Kashmir

HimachalPradesh

Punjab

UttarPradeshRajastha

n

Gujarat MadhyaPradesh

Bemina

J&K SEB• 1 SLDC • 1 Sub-LDC• 16 RTUs

PSEB• 1 SLDC • 2 Sub-LDC• 40 RTUs

HVPNL• 1 SLDC • 2 Sub-LDC• 42 RTUs

RVPNL• 1 SLDC • 3 Sub-LDC• 79 RTUs

HPSEB• 1 SLDC • 2 Sub-LDC• 16 RTUs

DVB• 1 SLDC • 4 Sub-LDC• 31 RTUs

UPPCL• 1 SLDC• 4 Sub-LDC• 55 RTUs

RLDC•NEW DELHI• 36 RTUs

CPCCKANPUR

6 RTUs SLDCSub - LDC

Gladni

Panki

ana Uttaranchal

• 1 SLDC•27 RTUs

BBMB• 1 SLDC • 4 Sub-LDC• 21 RTUs

Har

y

Moradabad

Varanasi

Sultanpur

Delhi

JutoghKunihar

Rishikesh

Unique Features of Northern Region ULDC Scheme

•Three Level Hierarchical Control centres

•More than ten electrical utilities involved

•Highly Complex system First Time attempted in the world as a Single Project

•Dedicated communication Infrastructure

•Live Line Fibre Optic Cable Stringing

•More than 30 control centres and 400 RTUs

•Advance Despatcher training Simulator

RTU DATA ACQUISITION SUPERVISORY CONTROL DATA EXCHANGE DATA PROCESSING (Alarms,

SOE,Generalized

calculations) DISTURBANCE DATA

COLLECTION HISTORICAL INFORMATION

STORAGE & RETRIEVAL (ISR)

SUPERVISORY CONTROL & DATA ACQUISITION (SCADA)

FUNCTIONS

OPERATION SCHEDULING

Load forecastingInflow forecastingUnit commitmentHydro schedulingHydro Thermal

CoordinationInterchange schedulingCurrent operating planOutage scheduling

POWER SYSTEM ANALYSIS

Network Topology

State estimationContingency

analysisOptimal power

flowTransmission

loss sensitivity factors

Post disturbance analysis

LOAD GENERATION BALANCE

Operation monitoringAGC Economic despatchReserve monitoringLoadshed /Restoration Production costing

EMS FEATURES

Dispatcher Training Simulator

Primary use:

Training of Dispatchers for routine and emergency scenario in a controlled and safe off-line manner.

Network split, blackouts

Large voltage or frequency excursions

Engineering tool for operations planning(generation plans, network switching,

etc..) and for understanding of power system behavior.

Thank You