Basics of Turbine Governing System

BTPS, NTPC LTDH K SETHI

WELCOME


SPRING

DISC

TURBINE

GENERATOR

CONTROL VALVE


TURBINE

CONTROL VALVE

GEN

M M M M


TURBINE ROTOR

WORM GEAR

SPRING

FLY WEIGHT

FIXED FULCRUM

CONTROL VALVE

SLEEVE

V

0

maxn1

n3n2

(n1-n3) x 100Droop (in %) =

(n1+n3) /2

H


FREQUENCY VS LOAD CURVE

50 Hz 52.5 Hz51.25 Hz

100%

50%

0% Frequency in Hz

Load in %

Assumption, Droop = 5 %


CHARACTERISTICS OF FREQUENCY INFLUENCE

Droop = 4 %

Droop = 8 %

48 5250

Frequency (in Hz)

+50 %

- 50 %Load

49 51


VARIATION IN LOAD IN A GRID

DROOP

3 % 4 % 5 %

100 % 1.5 Hz 2 Hz 2.5 Hz

50 % .75 Hz 1 Hz 1.25 Hz

25 % .375 Hz 0.5 Hz 0.625 Hz

10 % 0.15 Hz 0.2 Hz .25 Hz

5 % 0.075Hz 0.1 Hz 0.125 Hz

EFFECT OF DROOP SETTING ON GRID REQUENCY


INDIAN POWER SECTOR (DEMAND AND SUPPLY)


Region Energy Demand

Energy Available

Energy Shortage

Peak Demand

Peak Met

Peak Shortage

MU MU MU % MW MW MW %

Northern

82,885 76,077 -6,808 -8.2 24,092 21,889

-2,203 -9.1

Western 88,896 78,353 -10,543

-11.9

25,937 20,736

-5,201 -20.1

Southern

71,332 63,829 -7,503 -10.5

22,205 18,892

-3,313 -14.9

Eastern 26,301 25,569 -732 -2.8 8,076 7,676 -400 -5

North-Eastern

3,120 2,996 -124 -4.0 1,161 981 -180 -15.5

All India 2,72,534

2,46,824 -25,710

-9.4 79,443 68,581

-10,862

-13.7

INDIAN POWER SCENARIO (FROM APRIL – SEPT 2002)

Data taken from proceedings of National Seminar on “Grid Operation & Management” conducted by CBIP, New Delhi


Data taken from proceedings of National Seminar on “Grid Operation & Management” conducted by CBIP, New Delhi

0

10

20

30

40

50

60

70

80

% of Time

Region wise Frequency Profile (From Apr - Sept' 02)

< 48.5 Hz 1.12 24.09 72.46 4.96

48.5 – 49.0 Hz 8.18 17.58 13.11 11.62

49 – 50.5 Hz 73.85 53.05 13.13 48.05

50.5 – 51 Hz 14.18 4.54 1.29 15.7

> 51 Hz 2.67 0.74 0.01 19.67

Northern Western Southern Eastern & NE


EXAMPLE OF NORTHERN GRID

TOTAL INSTALLED CAPACITY= 28000 MW NORMALLY AVAILABLE POWER (APPROX.) = 17000 MW PEAK LOAD DEMAND IN A DAY (APPROX.) = 19000 MW HENCE TOTAL SHORTFALL IN A DAY = 2000 MW

(APPROX. 10%) THEREFORE, VARIATION IN GRID FREQUENCY

SHOULD NOT BE MORE THAN 0.25 Hz (=.1*2.5Hz). BUT

IN ACTUAL THE VARIATION IN FREQUENCY IS OF THE

ORDER OF 1-1.5 Hz.

ASSUMPTION :- DROOP = 5 %




FREE GOVERNOR MODE OF OPERATION

(FGMO)


WHAT IS FREE GOVERNOR MODE OF OPERATION ?

THE MAIN PURPOSE OF FREE GOVERNOR OPERATION IS

TO MAINTAIN NATIONAL GRID FREQUENCY AT 50 Hz

FREE GOVERNOR OPERATION ALLOWS THE MACHINE

TO LOAD OR UNLOAD DEPENDING UPON WHETHER

FREQUENCY IS LOWER THAN 50 Hz OR MORE THAN 50 Hz

RESPECTIVLEY

VARIATION IN GRID FREQUENCY CAN BE MINIMIZED BY

PUTTING ALL THE GENERATING STATIONS ON “FREE

GOVERNOR MODE OF OPERATION ”


GOVERNING SCHEME PART-1













GOVERNING SYSTEM CHARACTERISTICS

SETTING


S.N.

Gov Bellow

Aux F/U Piston

F/U Piston

Aux SOP

HP SOP IPSOP HPCV 1/2

IPCV 1/2

(Stroke in mm) (in Kg/cm2) (v/v Stroke in mm)

1. 0 0 0 2.3 2.5 - 0 -

2. 0.57 1.05 0.95 2.52 2.79 2.5 2.5 0

3. 1 1.84 1.66 2.68 3 3.18 4.5 6.8

4. 1.18 2.18 1.95 2.75 3.09 3.47 5 10.5

5. 1.3 2.4 2.16 2.79 3.15 3.66 5.5 16

6. 1.6 2.95 2.41 2.91 3.3 4.12 7 30

7. 2 3.69 3.32 3.06 3.5 4.76 8.8 75

8. 2.15 3.96 3.57 3.12 3.57 5 9.5 95

9. 2.5 4.61 4.15 3.25 3.75 11.8

10. 3.2 5.9 5.31 3.52 4.1 16.4

11. 3.9 7.19 6.47 3.78 4.45 25.5

12. 4.5 8.3 7.47 4.01 4.75 28.8

13. 5 9.22 8.3 4.2 5 50

GOVERNING SYSTEM CHARACTERISTICS SETTING


Governing System Characteristics

0

1

2

3

4

5

6

7

8

9

10

1 2 3 4 5 6 7 8 9 10 11 12 13

Stro

ke in

mm

GOVERNOR BELLOWS AUX. FOLLOW UP PISTON FOLLOW UP PISTON


Governing System Characteristics

2

2.5

3

3.5

4

4.5

5

5.5

6

1 2 3 4 5 6 7 8 9 10 11 12 13

Oil

Pres

sure

in K

g/cm

2

0

10

20

30

40

50

60

70

80

90

100

Valv

e st

roke

in m

m

AUX SOP HP SOP IP SOP HPCV1/2 IPCV1/2


LMW GOVERNING SCHEMES



THANK YOU

Documents

Basics of Turbine Governing System