NORTHERN REGIONAL GRID SYSTEM

CONTINGECY AND RESTORATION

NORTHERN RGIONAL GRID : TYPICAL CONDITIONS Typical location of the generating stations vis-à-vis load -- pit head thermal generating stations in the south-east part, -- most of the hydro stations in the north-west part and -- load concentration in the central part of the grid, thereby -- requiring to wheel large quantum of power for long distances

Region having largest number of constituents

-- 9 number of states/U.T and 3 numbers of C.S. Gen. agencies

-- Number of hydro projects having joint ownership -- Criss-crossing of transmission network owned by different agencies

Wide variation in the regional load profile

-- load crash of the order of 5000MW due to sudden change in weather -- steep fall in demand at certain instances, particularly during winter nights

Special requirements by some states

-- by J&K due to strategic location and weather conditions

-- by Delhi due to being capital and strategic nature of load

CHAMERA

DEHAR

HISSAR

MOGA

BHIWANI

PANIPAT

DADRI

RISHIKESH

MORADABAD

SULTANPUR

AZAM-GARH

GORAKHPUR

MAU

OBRA SARNATH

ANPARA

RIHAND

SINGRAULI

KANPUR

(PG)

AURAIYA

BALLABGARH

BAWANA

BAMNOLI

BASSI

JAIPUR

PANKI

MURADNAGAR

MANDAULA

VINDHYACHAL

MALERKOTLA

HYDRO

THERMAL

GAS

POWERGRID SUB-STATION

BBMB SUB-STATION

STATES SUB-STATION

400 kV UNSWITCHED

LINE REACTOR

33 kV SWITCHED

BUS REACTOR

400 kV SWITCHED

BUS/LINE REACTOR

STATIC VAR

COMPENSATOR

HVDC BACK TO BACK

LEGEND:-

NORTHERN BUS

WESTERN BUS

(63)

(50)

(50)

(50)

(50)

B(50)

(50)

540 MW

3x250 MVA

2x315 MVA

1x500 MVA 3x315 MVA

TRF 400/220 kV4x315 MVA

TRF 400/220 kV

2x240 MVA

TRF 400/220 KV2x240 MVA

TRF 400/220 kV2x240 MVA

2x240 MVATRF 400/220 kV 2x240 MVA

TRF 400/220 kV

TRF 400/132 kV2x200 MVA

TRF 400/132 kV2x100 MVA

TRF400/132kV3x100 MVA

A

A

TRF 400/220 kV3x250+1x315 MVA

B

B

B

B

B

99 km.

400 kV GRID DIAGRAM OF NORTHERN REGION

400 kV TRANSMISSION LINES

765 kV TRANSMISSION LINES

URI

WAGOORAPAMPORE 4x120 MW

TRF 400/220 kV2x315 MVA

TRF 400/220 kV

TRF 400/132 kV

NRLDC/POWERGRID

JANUARY, 2002

A

A

A

(50)

A

(50)

TRF 400/220 kV2x315 MVA

A(50)

A(50)

(50)

B

2x450 MVATRF 400/220 kV

A(50)

TRF 400/220 kV3x315 MVA

NATHPA JHAKRI

ABDULLAPUR

400/220 kV2x315 MVA

TRF 400/220 kV2x315 MVA

2x240 MVATRF 400/220 kV

LUCKNOW2x240 MVA

TRF 400/220 kV

2x240 MVATRF 400/220 kV

2x200 MVA

1x315 MVA

BARREILLY

UNNAO

A

(50)

HVDC 500 kV LINE

NALAGARH

+

TRF 220/132 kV2x150 MVA

TRF 400/220 kV

145 Km.

TRF 400/220 kV

TRF 400/220 kV

1x315 MVA

AGRA AGRA(UPPCL)

RATANGARH

SURATGARH

CHOMU

REENGUS

SIKAR

2x240 MVA

TRF 400/220 kV2x315 MVA

2x315 MVATRF 400/220 kV

TRF 400/220 kV2x315 MVA

B(63)

A(50)

TRF 400/220 kV2x315 MVA

B(50)

Charged at220 kV

220 kVCharged at

2x315 MVA

TRF 400/220 kV

TRF

DULHASTHI

Charged at400 kV

Charged at400 kV

JALLANDHAR

SCALE : NOT TO SCALE

(63)A

2x315 MVATRF 400/220 kV

1x315 MVATRF 400/220 kV

2x315MVATRF400/220kV

220 kV TRANSMISSION LINES

ALLAHABAD

FROM BIHAR SHARIF

TRF 400/220 KV2x315 MVA

DRN. BY Ramjit

SYSTEM CONTIGENCIES IN NORTHERN GRID Load generation imbalance

. -- Low Frequency -- High Frequency

Voltage related contingencies --Low Voltage --High Voltage

Failure of transmission network

System hunting

SYSTEM CONTINGENCIES : LOW FREQUENCY Sudden/gradual loss of generation --Failure of station’s auxiliary power supply --Critical fault in a sub-station area --Sudden interruption of gas supply in a GT plant --Station’s auxiliaries tripping due to voltage collapse --Tripping of evacuating circuits from a station

Sudden/gradual increase in load

Tripping of inter-regional links

Environmental effects --Choking of filters --Wet coal conditions

--Sudden inrush/depletion of water

SYSTEM CONTINGENCIES : HIGH FREQUENCY

Sudden/gradual loss of load due to change in weather conditions

Excessive generation due to PLF linked incentive/reward schemes

Excessive generation due to deficient commercial mechanism

Loss of load due to tripping of circuits/ICT’s

Tripping of inter-regional links

SYSTEM CONTINGENCIES : LOW VOLTAGE Inadequate VAR compensation at user’s end

Utilities drawing large VARS from the grid

Overloaded transmission/distribution network

Inadequate VAR generation by some generators

Deficient planning/design of sub-stations

Deficient commercial mechanism

SYSTEM CONTINGENCIES : HIGH VOLTAGE Unloading of the circuits due to sudden crash in

demand

Reluctance by generators to operate in leading mode

Improper switching of Reactors/Capacitor banks

Deficient planning/design of sub-stations

Deficient commercial mechanism

SYSTEM CONTINGENCIES : FAILURE OF TRANSMISSION NETWORK

Failure of Rihand-Dadri HVDC poles

Failure of circuits in 400KV AC network in east-west corridor

Incomplete 400KV ring aroud Delhi System

Simultaneous tripping of large numbers of EHV circuits in certain parts of the grid due to foggy and inclement weather coniditions

Failure of transmission circuits in J&K system

DADRI

MORADABAD

OBRA

ANPARA

RIHAND

SINGRAULI

KANPUR

(PG)

BALLABGARH PANKI

MURADNAGAR

VINDHYACHAL

400 kV GRID / TRANSMISSION LINES IN EAST-WEST

LUCKNOW

UNNAO

AGRA

AGRA(UPPCL)

Charged at400 kV

ALLAHABAD

DRN. BY Ramjit

BASSI

CORRIDOR OF NORTHERN REGION

220 kV TRANSMISSION LINES

400 kV TRANSMISSION LINES

G.T. POWER STATION

SUB STATIONS

THERMAL POWER STATIONS

LEGEND:-PROPOSEDEXISTING

220 kV U/G TRANSMISSION CABLES

SYSTEM CONTINGENCIES

Total blackout in northern grid during last few (6)years:

--20th December 1996

--2nd January 2001

Other partial disturbances:

--Disturbances due to failure of equipment

--Disturbances due to voltage collapse

--Disturbances due to critically low frequency