LOAD ANGLE MEASUREMENT USING SCADA

A UNIQUE VISUALISATION TOOL FOR GRID OPERATION

S.P.KUMARCM(SCADA-IT)

SRLDC, POWER GRID

NATIONAL GRID

QUICK FACTS

SOUTHERN REGION

WESTERNREGION

EASTERN REGION

NORTHERN REGION

NORTH-EASTERN REGION

INSTALLED CAPACITY

NORTHERN :- 33,782 MW

EASTERN :- 16,680 MW

SOUTHERN :- 37,054 MW

WESTERN :- 34,867 MW

NORTH-EASTERN :- 2,443 MW

TOTAL(APPROX) 125,000 MW

REGIONAL GRIDS

SOUTHERN REGION

WESTERNREGION

EASTERN REGION

NORTHERN REGION

NORTH-EASTERN REGION

‘ELECTRICAL’

REGIONS

1

2

WITH THE COMMISSIONING OF THE TALA PROJECT CONNECTING THE EASTERN AND NORTHERN GRIDS, INDIA WILL HAVE ONLY TWO GRIDS

30,500 MW

16,00037,140 MW

36,584 MW

Installed capacity & Inter regional links Inter regional

LinkMW capacity

NER-ER 1,850

ER-NR 2,700

ER-SR 1,200

ER-WR 1,650

SR-WR 1,200

WR-NR 900

Talcher Kolar HVDC Bipole

2,000

Total as on 31.08.06

11,500

Target for 2012

37,500

Two synchronous systems-North-Central & South

34,307 MW

16,478 MW

2,404 MW

Installed Generation CapacityCurrent : 126,994 MWTarget for Year 2012 : 200,000 MW

Figures as on 31-Aug-2006

Coal

Hydro

Energy Resource Map

OVERVIEW OF SOUTHERN REGIONAL GRID

SOUTHERN REGION – GEOGRAPHY

ANDHRA PRADESH

TAMIL NADU

KARNATAKA

KE

RA

LA

POPULATION :- 22.5 CRORES ( 22% OF INDIA)

AREA :- 651 (‘000 SQ KM)(19% OF INDIA)

INSTALLED CAPACITY:- 36,784 MW(29.5%)

WEATHER :- South-west monsoon

North-east monsoon

SEA COAST :- AROUND 4000 KM

GENERATING UNITS IN SOUTHERN REGION

A.PKAR

TNKERGENERATORS ABOVE 1000 MW

GENERATORS 500 – 1000 MW

GENERATORS BELOW 500 MW

TYPICAL

GENERATOR

SPREAD

IN SR

UNIT CAPACITY AP KAR KER TN CGS TOTAL

THERMAL (500 MW) 2 8 10

THERMAL

(200-250 MW)10 7 13 15 45

GAS/THERMAL

(100-150 MW)9 2 3 10 24

HYDRO

(>50 MW)27 29 16 15 87

TOTAL 48 38 19 38 165

- HYDRO

- THERMAL

- GAS / NAPTHA

- NUCLEAR

LOAD 500-1500 MW

LOAD 200-500 MW

TYPICAL

LOAD

SPREAD

IN SR

KHAMMAM

VIJAYAWADANAGARJUNASAGAR

GAZUWAKA

HYDERABAD

RAICHUR

GOOTY

HOODY

SALEM

UDUMALPET

TRICHUR

MADURAI

TRICHY

MADRAS

NEYVELI

CUDDAPAH

DAVANAGERE

RAMAGUNDAM

BANGALORE

MUNIRABAD

PP

P

P

P

P

P

P

P

P

P

PP

P

KOLAR

63

HOSUR

1

60

P

NELLORE

NELAMANGALA

KURNOOL

KALPAKKA

SIMHADRI

HIRIYUR

TALAGUPPA

MAMIDIPALLY

SRI SAILAM

-- OF NTPC

-- OF ANDHRA PRADESH

-- OF TAMIL NADU

-- OF NLC

-- OF POWERGRID

400KV SUB-STATIONS IN SR

NEYVELI TPS I (EXP)

  POWERGRID STATE OTHERS TOTAL

AP 8 9 2 19

KAR 6 5 1 12

KER 2     2

TN 6  1 2 9

TOTAL 22 15 5 42

TRIVENDRUM

NARENDRA

VEMAGIRIGMR

JEGRUPADU EXTN

MEHA BOOB NAGAR

CHITTOOR

-- OF NPC

KAIGA

MYSORE

-- OF KARNATAKA

ALMATHI

MONSOONS

SOUTH WEST MONSOON NORTH EAST

MONSOON

BACK

SR QUICK FACTS

• INSTALLED CAPACITY 37054 MW

– THERMAL: HYDRO 67:33

• PEAK DEMAND MET ≈ 23,000 MW

• MAX DAILY CONSUMPTION 525 MU

NUCLEAR STATION

KHAMMAM

VIJAYAWADAN’SAGAR

GAZUWAKA HYDERABAD

RAICHUR

GOOTY

BANGALORE

SALEM

UDUMALPET

TRICHUR

MADURAI

TRICHY

MADRAS

NEYVELI

GUTTUR

KAIGA

RSTPP

BHADRAVATI

`HOODY

MUNIRABAD

P

P

P

P

P

P

P

PP

P

P

N

KOLAR

TALCHER

JEYPORE

HOSUR

SSLMM

MMDP

THIRUVANANTHAPURAM

NELLORE

NELAMANGALA

KURNOOL

KALPAKKA

SIMHADRI

HIRIYURTALGUPPA

KADAPA

1000 MW HVDC BACK TO BACK LINK

2000 MW HVDC BIPOLE

500 KV HVDC LINE

400 KV LINE POWERGRID

400 KV LINE APTRANSCO

400 KV LINE KPTCL

400 KV LINE OPERATED AT 220 KV

THERMAL GENERATING STATION

NEYVELI TPS – 1 (EXP)

400KV SUB-STATION

NARENDRA

MAHABOOB NAGAR

CHITTOOR

VEMAGIRI

GVKGMR

MAPS

SRLDC, BANGALORE

MARCH 2006

Grid Performance77

57

72 1

53

72 13 4

0 0 0

74

0

10

20

30

40

50

60

70

80

90

2001-02 2002-03 2003-04 2004-05 2005-06

Total Minor Major

Number of Grid Disturbances

have come down

High Transmission System

Availability98.28 98.29

98.64

99.17

99.64

97

98

99

100

1992-93 1995-96 1998-99 2001-02 2005-06

LOAD ANGLE

AN EMPIRICAL TOOL

POWER SYSTEM STABILITY

• ‘Power system stability is the ability of an electric power system, for a given initial operating condition, to regain a state of operating equilibrium after being subjected to a physical disturbance, with most system variables bounded so that practically the entire system remains intact.’

---------------------------------------VLPGO ’05, WG1

STABILITY CLASSIFICATION

Power System

Stability

Thermal

Overloading

Rotor Angle

Stability

Small-Disturbance

Angle Stability

Transient

Stability

Frequency

Stability

Voltage

Stability

Large-

Disturbance

Voltage Stability

Small-

Disturbance

Voltage Stability

Cascading Blackouts

VLPGO 2005 WG1

WHY DO WE NEED A LOAD ANGLE DISPLAY ?

• SOUTHERN REGION WAS PLAGUED BY LOW VOLTAGES, HEAVILY LOADED LINES, LOW FREQUENCY PROBLEMS

• SKEWED LOADING ON LINES DUE TO LARGE DISTANCES BETWEEN LOAD AND GENERATION

• OPERATOR COULD NOT PERCIEVE HOW NEAR TO THE PRECIPE HE WAS

• SEPARATIONS/ GRID DISTURBANCES WAS THE ORDER OF THE DAY

• INTER AREA OSCILLATIONS WERE NOTICED FREQUENTLY• DECREASING GENERATION/LOAD SHEDDING IN SELECTED

PLACES HELPED ALLEVIATE THESE SYMPTOMS• LOAD ANGLE WAS CALCULATED AND STORED

– MANY DISTURBANCES WERE ANALYSED AND AN EMPIRICAL LIMIT WAS CONCIEVED

– LOAD ANGLE FOR EACH CRITICAL LINE AND CORRIDOR IS DISPLAYED

LOAD ANGLE- VISUAL DISPLAY

• DATA FROM ALL STATIONS ARE AVAILABLE AT 10 SEC REFRESH RATE

• COMPUTATION OF ANGLE IS DONE AT RSCC SERVER

• LINE WISE AND CORRIDOR WISE LOAD ANGLE DISPLAY IS GIVEN TO OPERATOR

• GENERALLY LIMITED TO 50O FOR CORRIDOR AND 20O FOR SINGLE HOP FOR CRITICAL LINKS

LOADANGLE AND POWERLEVEL RELATION FOR DIFFERENT LINE LENGTHS

Power Level in MW

Lo

ad A

ng

le i

n d

eg

rees

0

5

10

15

20

25

100 200 300 400 500 600

350KM line200KM line100KM line

Loadangle and Voltage (Receiving end) relation for different line lengths

3

5

7

9

11

13

15

17

19

21

400 390 380 370 360 350 340 330 320 310 300

VOLTAGE AT RECEIVING END

Lo

ad A

ng

le in

deg

rees

350KM line200KM line100KM line

Load Angle Between Ramagundam and Neyveli Typical day plot

30

35

40

45

50

55

60

650 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

Time in hrs

An

gle

in d

egre

es

LOAD CHANGE OVER BY AP SKEWS LOADING PATTERN

LOAD ANGLE OF RGM-NLY DURING A SYSTEM SEPARATION

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

HOURS------------>

LO

AD

AN

GL

E I

N D

EG

RE

E

SYSTEM SEPARATION POINT

CHART SHOWING LOAD ANGLE WITH REFERENCE TO SIMHADRI BUS AT VARIOUS STATIONS FOR DIFFERENT POWERFLOW BETWEEN AP-KAR AND KER -TN SYSTEM

0

5

10

15

20

25

30

35

40

45

50

SIMHADRI GAZUWAKA VIJAYAWADA NELLORE SRIPERUMBUDUR NEYVELI

STATIONS

AN

GU

LAR

DIF

FER

AN

CE

IN D

EGR

EES

900MW

1100MW

1350MW

1550MW

CHART SHOWING LOAD ANGLE WITH REFERENCE TO RAMAGUNDAM BUS AT VARIOUS STATIONS FOR DIFFERENT POWERFLOW BETWEEN AP-KAR AND KER -TN SYSTEM

0

5

10

15

20

25

30

35

40

RAMAGUNDAM N'SAGAR CUDDAPAH SRIPERUMBUDUR NEYVELI

AN

GU

LAR

DIF

FER

AN

CE

IN

DEG

RE

ES

900MW

1100MW

1350MW

1550MW

1550MW WITH A TRUNKLINEOUT

Visualization Techniques

Inputs used

• Vindhyachal North Bus L-L Voltage.• Angular Separation between Vindhyachal

North Bus and West Bus. ( Available through Phase angle transducer having one input through R-Phase

North Bus and another through R-Phase West Bus having range only up to 60 degree)

• Phasor Voltage difference between Vindhyachal North Bus and West Bus ( Available through voltage transducer having one input through R-Phase North Bus and another through R-Phase West Bus)