TABEL PROTEKSI

TABEL PROTEKSI PADA SALURAN TRANSMISI

Macam Proteksi Uraian

Over current Protection

- Klas waktu dan Arus

- Directional atau

tidak directional

Merupakan pengaman utama untuk

saluran distribusi dan back-up

untuk saluran utama, dimana

pengaman utamanya adalah jarak

atau tipe lain yang cepat

Waktunya minimum rele inverse

definite dipilih untuk sistem waktu

yang sempit

Rele Instantaneous untuk arus

Proteksi gangguan ke tanah Pengaman gangguan ke tanah

terpisah yang ditambahkan hanya

untuk kebutuhan pengaman

gangguan phasa ke tanah

Pengaman Jarak Lebih cepat dari pengaman over

current. Kombinasinya tergantung

pada panjang saluran yang on

Pilot wiredifferential protection Untuk saluran transmisi yang

panjang (minimal 10 km)

Carrier Current Protection Untuk saluran transmisi yang

panjang dan sering terbukanya CB

TABEL PROTEKSI PADA GENERATOR

Teknik Elektro ITS 1

TABEL PROTEKSI

No

.

Macam Proteksi Kurang

dari

1 MW

Diatas

1 MW

Diatas

1 MW

Diatas

1 MW

1. Differential * *

2. Restriced earth fault * *

3. Stator turn to turn fault *

4. Time Over Current * *

5. Temperature

(thermo-detector)* * *

6. Negative sequence

Current* * *

7. Loss of Load * *

8. Loss of input-anti-

Motoring* * *

9. Loss of field * *

10. Loss of synchronism * *

11. Over speed*

Hanya untuk

hydrogenerator

12. Over voltage*

Hanya untuk

hydrogenerator

13. Rotor earth fault * *

14. Back-up overcurrent * * *

15. Bearing temperature * *

16. Bearing insulation *

Teknik Elektro ITS 2

TABEL PROTEKSI

TABEL BEBARAPA KONDISI TIDAK NORMAL

DAN SISTEM PENGAMANNYA

No. Kondisi tak normal Pengaruh Pengaman

1. Panas Kelebihan

beban

- beban naik terus

- sistem pendingin

rusak

Kumparan stator

dan isolasi rusak

karena terlalu

panas

Thermocouples atau

resistance

thermometer

imbedded in stator

slots and cooling

system.

Stator overload

protection with

overcurrent relay

2. Gangguan diluar

generator

Beban tidak

seimbang,

tekanan pada

kumparan dan

poros, panas

berlebihan yang

memperpanjang

hubung singkat.

Negative sequence

protection untuk

mesin yang besar.

Overload protection

untuk mesin yang

kecil

3. Gangguan pada

stator:

- antar phasa

- phasa ke tanah

- inter turn

Kumparan

terbakar,

pengelasan pada

inti laminasi, mati

Blased differential

protection, sensitive

earth fault protection,

inter turn fault

protection

Teknik Elektro ITS 3

TABEL PROTEKSI

No. Kondisi tak normal Pengaruh Pengaman

4. Rotor gangguan ke

tanah

Satu gangguan

tidak berbahaya,

kedua gangguan

menyebabkan

ketidakseimbanga

n tekanan magnet

yang

menyebabkan

kerusakan shaft

dan bearing.

Rotor earth-fault

Protection

5. Kehilangan medan

magnet

- CB medan magnet

trip

Generator jalan

sebagai generator

induksi yang

mendapat eksitasi

arus dari bus-bar.

Kecepatan

bertambah

Loss of field atau field

failure protection

6. Generator berubah

jadi motor.

Saat inpit dari prime

mover berhenti,

generator mangambil

daya dari bus-bar dan

berubah menjadi

motor sinkron pada

keadaan yang sama

Pengaruhnya

tergantung pada

prime mover yang

on dan jumlah

daya yang diambil

dari bus-bar saat

berubah jadi

motor

Reverse power

protection by

directional power

relays detect the

reversal of power

7. Over voltage Isolasi terbakar Ligthning arrester

tersambung pada

terminal generator.

Teknik Elektro ITS 4

TABEL PROTEKSI

TableTypes of protection for Generators and their setting

Generator Rating

1

Type of Drive

2

Type of protection used

3

Suggested fault current setting

4

Protection for exciter circuit and neutral

5

Below 1000 KVA

Steam Turbine

1.fault relay

2.current relay

3.(only for back pressure turbines)

20 percent full load current 125 percent full load current 10 to 20 percent of its normal power rating

1. Neutral isolating switch

2. Field switch in the exciter field circuit

Steam Engine

or Diesel Engine

1. Time graded earth fault relay

2. Time graded over current relay

3. Reverse power

20 percent full load current 125 percent full load current 10 to 20 percent of its normal power rating

1. Neutral isolating switch

2. Field switch in the exciter field circuit

1000 KVAto

5000 KVA

Steam Turbine

1. Balanced earth fault relay or

Differential protection (Merz-Price)2. Reverse power

(only back pressure turbine)

10 to 25 percent full load current 10 to 25 percent full load current 10 to 25 percent full load current

1. Neutral isolating switch

or Automatic neutral breaker

1000 KVAto

5000 KVA

Water Turbine

1. Balanced earth fault relay or

Differential protection (Merz-Price)2. over voltage

protection

10 to 25 percent full load current 10 to 25 percent full load current 10 percent of normal voltage

1.For unattended elations, protection against field failure Setting 20 to 30 percent of the normal excitation.2.Neutral isolating switch or automatic neutral breaker

Teknik Elektro ITS 5

TABEL PROTEKSI

Generator Rating

1

Type of Drive

2

Type of protection used

3

Suggested fault current setting

4

Protection for exciter circuit and neutral

5

Above 5000 KVA

Steam Turbine

1. Differential protections (Merz-Price)

or Time graded earth fault

relay2. Phase unbalance

3. Reverse power (only back pressure turbine)

10 to 25 percent full load current 20 percent full load current 10 to 25 percent negative phase sequence only 10 to 25 percent full load current

1. Field earth fault for protecting 96% of the field winding (only for generator above 20.000 KVA)2.Automatic field suppression switch

3.Automatic neutral breaker.

Water Turbine

1. Differential protections or Time graded earth fault

relay2.Over voltage

10 to 25 percent full load current 20 percent full load current 10 percent of normal voltage

1.For unattended station protection against field failure, Sotting 20 to 30 percent normal excitation2.Filed earth fault for protecting 96% of the field winding.3. Automatic field suppression switch3.Automatic neutral breaker.

Teknik Elektro ITS 6

TABEL PROTEKSI

Table Power Transformer Protection

Abnormal Condition Protection Remarks

Incipient faults below oil level

resulting in decomposition of oil,

faults between phases and between

phase and ground

Buchholz relay sounds

alarm (Gas actuated relay)

Buchholz relay used for

transformer of rating 500 KVA

and above

Large internal faults phase to phase,

phase to ground, below oil level

1. Buchholz relay trips the

circuit breaker

Buchholz relay too slow and less

sensitive

2. Merz Price percentage

differential protection

3. High speed high set

overcurrent relay

Merz Price percentage

differential protection used for

transformers of and above 5

MVA

Earth faults

1. Merz Price percentage

differential protection

For transformer of and above 5

MVA

2. Earth fault relay a. Instantaneous Restricted

E.F. Relay

b. Time lag E.F Relay

Through faults

1. Graded time lag over

current relay

Protection of distribution

transformer

2. H.V Fuses Small distribution transformer up

to 500 KVA

Overloads

1. Thermal overload relay

2. Temperature relays

sound alarm

Generally temperature indicators

are provided on the transformers.

Temp. increase is indicated on

control board also. Fans started

at certain temp.

Teknik Elektro ITS 7

TABEL PROTEKSI

Abnormal Condition Protection Remarks

High Voltage Surges due lightning,

switching

1. Horn gaps Not favoured for important

transformer

2. Lightning arresters In addition to L.A.s for incoming

lines

Small distribution transformer

Only fuses for earth fault protections and phase fault

protection. Overload protection generally not

provided

For more important transformers of about 500 KVA

Over current relays

Instantaneous earth fault relays

Transformers in important locations ratings 500

KVA and above

Restricted earth fault protection

Over urrent protection

Buchholz relay

Teknik Elektro ITS 8

TABEL PROTEKSI

Table Protection of Large Generator Transformer Unit

Protection of Generator

Transformer together

Generator-transformer overall differential protection*

Generator protection Generator differential protection*

Stator earth fault protection*

Negative phase sequence protection against-

unbalanced loading***

Inter-turn fault protection

Reverse power protection

Field failure protection**

Rotor earth fault protection

Temperature sensors in slots***

Overcurrent relays in stator and rolar circuits

Lightning arrester for generator overvolatage protection

Protection of unit

auxiliary transformer

Differential protection*

Restricted earth fault protection*

Buchholz relay

Overcurrent protection

Winding and oil temperature sensors

Protection of main

transformer

HV overcurrent protection*

HV Restricted earth fault protection*

Buchholz relay

Winding and oil temperature sensors

Lightning arresters on HV side

Teknik Elektro ITS 9

TABEL PROTEKSI

Protection of Generator

Transformer together

Generator-transformer overall differential protection*

Preventive measures

sound alarm on control

panel

Continous monitoring of outlet temperature of gaseous

or liquid coolants

Flow monitors

Low noiler pressure alarm/trip

Lubrication oil failure

Emergency trip

Low vacuum

* Trip generator c.b., close throttle valves, open field c.b.,open auxiliary c.b

** Close emergency throttle valves main c.b. opened only after operation of

interlocking reverse power relay

*** Trip main circuit breaker only

Teknik Elektro ITS 10

TABEL PROTEKSI

Protection Chart for Induction Motors

Abnormal

condition

Alternate forms of protections

from which choice is made

Remarks

Overload - Overload release

- Thermal overload relays

- Inverse overcurrent relays

- Miniature circuit breaker

with built in trip

- overload protection givem for

almost all motors

Phase fault and

earth faults

- HRC fuses

- High set instantaneous

overcurrent relays

- Differential protection

- Differential protection

becomes economical for

motors above about 1200

HP. Below this high set

instantaneous protection is

preferred

Undervoltage - undervoltage release

- undervoltage relays

- undervoltage release

incorporated every

starter

- undervoltage relays used

in certain applications

Unbalanced

Voltage

- Negative phase sequence

relay

- only in special

applications

Reverse phase

sequence

- Phase reversal relays - Generally at support

Teknik Elektro ITS 11

TABEL PROTEKSI

point

- Prevents reverse of

running

Abnormal

condition

Alternate forms of protections

from which choice is made

Remarks

Single Phasing - Usual thermal overload

relays

- Special single phase

preventer

- Recently developed

static single phasing

devices becoming

popular

Stalling - thermal relays

- Instantaneous O.C Relays

Rotor Faults - Instantaneous overcurrent

relays

- only for motors

Teknik Elektro ITS 12

TABEL PROTEKSI

Teknik Elektro ITS 13