power generator for mt-8b

Power Generator

Iqbal Nusya PerdanaElectrical Facilities & Project Engineering

2 2

Basic Generator

Generator Operations

Generator Protection

Generator Maintenance

AGENDA

3 3

Basic Generator

4 4

DISCUSSION

Convert mechanical energy into electrical energy A direct result of Faraday’s work on induction Basically, the inverse of the electric motor which converts electrical

energy to mechanical energy

Mechanical Energy

Electric Generator Electrical Energy

5 5

Faraday Laws

1st Whenever a conductor cuts a magnetic field vv an emf is induced in it.

2nd The magnitude of induced emf is equal to the rate of change of flux linkage.

Ne

t

e induced emfN number of turns of coil/t rate of flux change

6

Basic Generation

U S

a

b

U S

ab

U S

a

b

U S

ab

0o 90o

180o 360o

Wt

-Vm

1 cycle

V = Vm sin Wt + 0o

270o1 Cycle

ω = 2 ∏ f

f = electrical frequency, usually 50 Hz or 60 Hz

7

the units of frequency (hertz or cycles/sec.)The frequency of the generated voltage is dependent on the number of field poles and the speed at which the generator is operated, as indicatein Equation :

where:f = frequency (Hz) P = total number of poles N = rotor speed (rpm) 120 = conversion from minutes to seconds and from poles to pole pairs

Frequency

120

N Pf

8

Generator Construction

Single Phase – Pole Outside Single Phase – Pole Inside

U S

9

Generator Construction

Single Phase – 2 Poles 3 Phases Generator

A1 A2U U

SS

U S

A1

A2

B1

B2

C2

C1

1010

Generator Parts

11 11

Prime Mover

The prime mover is the component that is used to drive the AC generator.

The prime mover may be any type of rotating machine, such as a diesel engine, a steam turbine, gas turbine or others

Rotor

The rotor of an AC generator is the rotating component of the generator.

The rotor is driven by the generator’s prime mover, which may be a steam turbine, gas turbine, or diesel engine.

Depending on the type of generator, this component may be the armature or the field.

The rotor will be the armature if the voltage output is generated there; the rotor will be the field if the field excitation is applied there.

Generator Parts

1212

Stator

The stator of an AC generator is the part that is stationary.

Like the rotor, this component may be the armature or the field, depending on the type of generator.

The stator will be the armature if the voltage output is generated there; the stator will be the field if the field excitation is applied there

Slip Rings

Slip rings are electrical connections that are used to transfer power to and from the rotor of an AC generator .

The slip ring consists of a circular conducting material that is connected to the rotor windings and insulated from the shaft.

Brushes ride on the slip ring as the rotor rotates. The electrical connection to the rotor is made by connections to the

brushes. Slip rings are used in AC generators because the desired output of

the generator is a sine wave.

Generator Parts

13 13

Field

The field in an AC generator consists of coils of conductors within the generator that receive a voltage from a source (called excitation) and produce a magnetic flux.

The magnetic flux in the field cuts the armature to produce a voltage. This voltage is ultimately the output voltage of the AC generator.

Armature

The armature is the part of an AC generator in which voltage is produced.

This component consists of many coils of wire that are large enough to carry the full load current of the generator.

Generator Parts

14 14

Generator Operation

15

Generator Nameplate

Typical name plate data for an AC generator includes: manufacturer serial number and type number; speed (rpm), number of poles, frequency of output, number of phases, and

maximum supply voltage; capacity rating in KVA and kW at a specified power factor and maximum output

voltage; armature and field current per phase; and maximum temperature rise.

16

Brushless Exciter Generator

16

17

Brushless Exciter Generator with PMG

18

BASIC GENERATOR CONTROL

a. Speed Controller

• Frequency is controlled by controlling speed, which is proportional to frequency.

• The speed governors for large machines with mechanical hydraulic governors are

set to the required speed by a governor motor.

• Those using electro-hydraulic governors are set by a speed adjusting

potentiometer.

• Both are controlled from the switchboard.

• The speed governors for small machines not equipped with governor motors

cannot be set to the required speed from the switchboard. These must be set by

manual adjustment at the governor.

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b. Voltage.

• Output voltage is controlled automatically by a voltage regulator.

• Automatic voltage regulators (AVR) are provided with a transfer switch

which permits a shift to manual voltage control in case of trouble in the

voltage regulator.


20

c. Load division.

The division of kilowatt load between two ac generators operating in parallel is

controlled by the settings and characteristics of the prime mover governors and

is not affected by the voltage control, either manual or automatic.


21 21

GENERATOR POWER FACTOR

Power factor is defined as the ratio real power to apparentPower.

This definition is often mathematically represented as kW/ kVA.

Where the numerator is the active (real) power and the denominator is the (active + reactive) or apparent power.

22 22

Power Triangle

P = Active Power Q = Reactive Power S = Apparent Power

23 23

From the above diagaram: I = Armature current, apparent power ( S ) I. Cos Q = Real power ( P ) I. Sin Q = Reaktive power ( Q )

Power Triangle

25 25

GENERATOR VOLTAGE REGULATOR

Voltage regulator maintenance :

- Visually check

- Keep cleaning (free of dirt, moisture or foreign material

- Keep electrical connection is good (tightened etc.)

- Inspect wiring from potential worn, cut or burn

- Remove oil or grease contaminant if any.

- Keep ventilating in good condition

Understanding of principles of regulator operation is very helpful

26 26

VOLTAGE REGULATOR SINGLE LINE DIAGRAM

27 27

VOLTAGE REGULATOR BLOCK DIAGRAM

29 29


TROUBLE PROBABLE CAUSE REMEDY

No Voltage - Open or short circuit between PMG and exciter field

-Prime mover not up to rated speed

-Defective regulato

- Defective exciter

Locate and repair

Adjust and repair

Check power circuit

Check field current

Voltage Regulator Troubleshooting Guidance

30 30



Low Voltage -Volts adjust rheostat (VAR) or R12 improperly adjusted

- VAR circuit open

-Speed of generator low

-Under frequency adjustment wrong

- Voltmeter not reading properly

Adjust

Check wiring and rheostatAdjust

Re-adjust of R47 very slowly until voltage stableReplace

31 31


High Voltage -VAR or R12 improperly adjusted

-No sensing voltage available at the regulator terminals

- Sensing transformer T1 and T2 connected wrong tap

- Defective rectifier diode D3

- Defective voltage regulator

- Voltmeter not reading properly

Adjust for more resistance

Check connection, fuses etc.

Check connections

Replace rectifier module

Perform bench test

Replace

32 32



GeneratorVoltage hunting (oscillating) at no load

- Frequency unstable

-Improperly adjusted stabilizing circuit

-Regulator output too low

-Defective exciter or generators

- Defective PC board

Check prime mover speedAdjust R33

Add series resistance in field circuit

Check exciter field current

Replace

33 33



Generator voltage fluctuating withirregular intervals

- Loose connection

- Induced interference

- Field voltage too low

Check

Twist VAR and sensing leads

Add resistance in series with field

34 34



Poor generatorvoltage regulation

- Voltmeter in different location than regulator sensing point

- Reactive current compensation causing droop

- Too much resistance in exciter field circuit

-Supply voltage at terminals 3 and 4 too low

- Defective PC board

Connect voltmeter across regulator terminals E1 and E3

Make inoperative by shorting secondary side of CT and open wiring at regulator terminals 1 and 2

Check regulator output voltage

Check and adjust

Replace

35 35



Parallel generation not dividing real (KW) load

- Prime mover governor not properly adjusted

Refer to governor instruction

36 36


Parallel generators not dividing reactive (KVAR) load

- Rheostat R3 shorted out or set for insufficient resistance

- CT connected with reverse polarity

- CT secondary terminals shorted out

-CT not in proper generator phase with respect to sensing voltage

- Unit parallel switch (if used) closed

Check, add resistance if necessary

Reverse connections

Check current (between 3-5 amp) at regulator terminals 1 or 2. Do not open circuit under load

Check and replace

Check


37

GENERATOR OPERATION MODE

DROOP (LOAD CONTROL)

• Base load, constant load at constant frequency

ISOCHRONOUS (FREQ. CONTROL)

• Swing unit, load change as demand, maintain frequency at 50Hz

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DROOP MODE

SP

EE

D

10%

5%

3%

0%

100%

Load

50%0%

CB

A

75%25%

39

ISO MODE

Droop

100%50%0%

0%

LOAD

75%25%

SP

EE

D

40

Generator Driver Operation Mode Governor

31PG-1 DG DROOP -

31PG-2 STG DROOP Back Pressure


31PG-4 STG ISOCH Condensing










31PG-15 GTG ISOCH -

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Generator Protection

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REACTOR

REACTOR

NEW 31PG-1

30PS-4, 13.8KV

352-15

352-13

31PG-8

352-4352-1 352-2 352-3

352-6

352-5

30PS-1, 13.8KV

TRAIN A/B, UTILITY A/BCW PUMPS 1 ~ 51st LOADING DOCK

COMMUNITY

TRAIN C/D, UTILITY C/DCW PUMPS 6 ~ 10

STORAGE & LOADING AREACOMMUNITY

30PS-101, 34.5 KV ( MODULE-1 )

30PT-101 30PT-102 30PT-103 30PT-104

31PG-1 31PG-2

30PS-2, 13.8KV

31PG-331PG-4

31PG-531PG-6

30PS-3, 13.8KV

30PT-201

30PS-201, 34.5 KV ( MODULE - 2 )

TRAIN G/H, UTILITY G/HCW PUMPS 16 ~ 22

352-7

352-12

352-16

352-14 352-8 352-9 352-10 352-11

TRAIN E/F, UTILITY E/FCW PUMPS 11 ~ 15

LPG & 2rd / 3th LOADING DOCK

30PT-202

31PG-9

30PS-5, 13.8KV

31PG-11 31PG-12

30PT-203

30PS-6, 13.8KV

31PG-1031PG-14

30PS-7, 13.8KV

30PT-204

31PG-1331PG-15

30PS-8, 13.8KV

TVP

S I N G L E L I N E D I A G R A M P O W E R

G E N E R AT I O N

43

86G

51V32 46

40X

51GN

87G

87GG

60

GOVERNOR

252

CB

40L

59

413 x CT1000/5

3 x CT1000/5

3 x CT1000/5

3 x CT1000/5

1 x CT100/5

1 x CT100/5

1 x CT1/10

2 x PT120/1

MPT

VRPT

G

TURBIN

HIGH RESISTENCE GROUDING

GROUNDING

BUSBAR 13.8 KVMANUAL CONTROL SWITCHS

BUS DIFFERENTIAL

CT. Connection

PT. Connection

TRIP. Connection

Bus Line

3 x CT1000/5

P R O T E C T I O N S Y S T E M

4444

No. DEVICE REMARK MODEL

1. 32 Reverse power / Anti motoring delay GGP53B

2. 40 Loss of excitation / Loss of field relay CEH51A3A

3. 46 Negative sequence delay INC77N2A

4. 51 V Voltage restraint time overcurrent relay IFCV / IJCV

5. 51 GN Generator ground relay IAC

6. 59 Over voltage relay IAV52A4A

7. 60 Voltage balance relay NGV12A11A

8. 87 G Generator differential relay CFD22B3A

9. 87 GG Generator differential ground relay ICC

10 86 G Lock Out relay

45

Since the fault of the generator from the system will interrupt the operation of electric power systems.

Generator needed to be protected from all the fault that will damage the generator.

Generator damage will disturb the supply of electricity.

Cause selectivity of the protection system, CB is expected to not easily trip because of fault in the system.

Introduction

46

This protection protects generator winding against internal faults such as phase-to-phase and three phase-to-ground faults. This type of fault is very serious because very large current can flow and produce large amounts of damage to the winding if it is allowed to persist.

Stator Differential (87G)

47

Current Unbalance – Negative Phase Sequence (46)

This protection protects generator when generator is supplying an unbalanced load to a system, a negative phase sequence current is imposed on the generator.

The negative sequence current in the stator winding

48 48

This protection protects generator when generator loss of excitation. Loss of field or loss of excitation results in loss of synchronism between rotor flux & stator flux. The synchronous machine operates as an induction machine at higher speed and draws reactive power from the grid.

Loss of Excitation (40)

49 49

Reverse Power (32)

This protection protects generator and prime mover (turbine) when generator acts as motor (draw out power from the grid). Motoring of a generator will occur when turbine output is reduced such that it develops less than no-load losses while the generator is still on-line, the generator will operate as a synchronous motor and driving the turbine.

50 50

Time Overcurrent Voltage Restraint (51V)

Normally generators are designed to operate continuously at rated MVA, frequency and power factor over a range of 95 to 105% rated voltage. Operating the generator at rated MVA with 95% voltage, 105% stator current is permissible.

51 51

Thermal Overload (49)

Thermal protection for the generator stator core and windings may be provided for the following contingencies:• Generator overload• Failure of cooling systems• Localized hot spots caused by core lamination insulation failures or by

localized or rapidly developing winding failures

52 52

Stator Earth Fault Protection (59N/64N)

Normally the generator stator neutral operates at a potential close to ground. If a faulty phase winding connected to ground, the normal low neutral voltage could rise as high as line-to-neutral voltage depending on the fault location

53 53

Over Voltage (59)

Generator voltage is at present value under normal operating conditions as selected by operator in AVR. If it parts from preset value, May be due to AVR mal-functioning or a system disturbance. Severe over voltage can cause over fluxing and winding insulation failure.

Over Excitation (24)

Per unit voltage divided by per unit frequency commonly called Volts/Hertz is a measurable quantity that is proportional to flux in the generator or step-up transformer cores. Moderate over fluxing (105-110%) increases core loss resulting in increase of core temperatures due to hysterics & eddy currents loss.

54

Neutral Grounding of generator

Generator commonly used Grounding with resistance that limits ground current

until 100 ampere.

Another way is grounding through the transformer pole, the system is

appropriate for large capacity machine. Grounding is worked through the high

voltage windings on the transformer pole by inserting resistance in the low

voltage side to restrict the grounding current until 5-15 Ampere.

56

Load Shedding SystemLoad shedding system is loads release in automatically during disturbance or problem, either from power generation side or loads side led to the frequency drop until certain secure value

By releasing loads that uncritical, continuity and reliability of the power system will be maintained

Loads release using the under frequency relay (81) with different setting in ref. with loads priority (through feeders). The lowest priority is community, support facilities and all the loads that is not connection with plant operation

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L O A D S H E D D I N G S Y S T E MSTEP 1

• Freq setting 49 Hz

STEP 2

• Freq setting 48.7 Hz

STEP 3

• Freq setting 48.3 Hz

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RELAY STEP SETTING FEEDER LOAD

81-1 Step 1 49.0 Hz 252-12 PSF Area

252-15 S/L Substation

252-18 Community

81-3 Step 3 48.3 Hz 252-162 CWP Motor No.2

252-163 CWP Motor No.1

81-2 Step 2 48.7 Hz 252-21 PSF Area

252-25 S/L Substation

252-28 Community

81-4 Step 4 48.0 Hz 252-262 CWP Motor No.3



59

M1 M2 M4M3 M5

2 1 2 3 4134

TIE

32-P

T-16

1

32-P

T-26

1

SPAR

E

01 02252-160

252-160/260

252-26032-PS-16/26

32-G

M-1E

13.8

KV, 4

424 H

P

32-G

M-1D

13.8

KV, 4

424 H

P

32-G

M-1C

13.8

KV, 4

424 H

P

32-G

M-1B

13.8

KV, 4

424 H

P

32-G

M-1A

13.8

KV, 4

424 H

P

CWP

30-F

DR-2

6

G1 G2 G3 G4

31-PG-113.8 KV, 5 MW

31-PG-213.8 KV, 12.5 MW

31-PG-313.8 KV, 12.5 MW

31-PG-413.8 KV, 12.5 MW

01 0102 02 4321

12 13 14 15 16 17 18 SP 21 22 2623 24 25 27 28

30-PS-1 30-PS-213.8 KV 750 MVA 13.8 KV 750 MVA

SP SP

SWGR BUS.1&2

Community CommunityPSFPSF SubstationPlant # 24

SubstationPlant # 24

81-1Step-149HZ

81-2Step-3

48.3 HZ

81-3Step-2

48.7 HZ

81-4Step-4 48.HZ

60 60

81-9

81-9. Step-1

81-10

81-10. Step-3

81-11

81-11. Step-2

81-12

81-12. Step-4

G

R

MASTER SWITCHLOAD SHEDDING

LOAD SHEDDING ACTIVE

LOAD SHEDDING IN ACTIVE

125 VDC

P R O T E C T I O N S Y S T E M

power generator for mt-8b

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