05 Pengaman Gen

RE1501 PERLENGKAPAN PUSAT PEMBANGKIT LISTRIK

RE1501 Perlengkapan Pusat Pembangkit ListrikPower Generation Equipment

Sem. VI 2SKS

Tujuan:Mempelajari dan memahami berbagai jenis perlengkapan listrik yang digunakan pada

pusat pembangkit tenaga listrik.Materi:Generator, konstruksi, sistem pendingin, penguatan dan pengaturan tegangan,

pengaman; transformator di pembangkit 3x1 phasa dan 1x3 phasa, grafik pembeban, system pendingin; sistem unit dan ril pada hubungan generator dan transformator, rangkaian pemakaian sendiri, panel hubung, lemari hubung; peralatan switchyard, circuit breaker, disconnecting switch, sistim ril pada switchyard.

Prasyarat:Analisa Sistem Tenaga I dan Mesin Arus Bolak Balik IIDaftar Pustaka:1. L. Baptidanov, V. Tarasov, “Power Station and Sub Station“, Peace Publisher,

Moscow 2. Sunil S. Rao, “Switch Gear and Protection“, Khana Publisher, New Delhi3. R.T Lythall, “J&P Switchgear Book “, Butterworth and Co. Publisher, London

1 Pendahuluan

2 Generator sinkron, klasifikasi dan konstruksi

3 Sistem penguatan pengatur tegangan otomatis dan pengaman

4 Transformator jenis dan konstruksi

5 Panas dan arus lebih yang dijanjikan

6 Sistem hubungan rangkaian utama hubungan generator dan trafo

7 Rangkaian untuk pemakaian sendiri

8 Ujian Tengah Semester

9 Ujian Tengah Semester

10 Sistem kontrol pada pusat listrik

11 Panel hubung, lemari hubung, ril pada listrik

12 Circuit braeker, proses pemadaman busur api, rangkaian trip

13 Jenis CB, konstruksi, rating, prinsip kerja, mekanisme penutupan CB, perhitungan pemilihan rating dari CB

14 Disconnecting Switch, earthing switch, load break switch dan pemasangannya

15 Sistem busbar, sistem tanpa ril, pemilihan SHR

16 Bahan dan bentuk Busbar, hubung singkat pada busbar

17 Ujian Akhir Semester

18 Ujian Akhir Semester

[1] “Modern Power Station Practice” vol. 4: Generator and Electrical Plant, Central Electricity Generating Board, Pergamon Press, 1971

[2] “Handbook of Electrical Engineering For Practitioners in the Oil, Gas and Petrochemical Industry”, Sheldrake, Wiley, 2003

[3] “Operation and Maintenance of Large Turbo-generators”, Klempner, Kerszenbaum, IEEE and Wiley Interscience, 2004.

[4] “IEEE Std C37.102-1995: IEEE Guide for AC Generator Protection”, IEEE, 1996

review Generator grounding Characteristics of Generators (overcurrent

characteristic)

[

[4] p. 14

Protectionrequirements

Gen stator thermal prot

Generatoroverload

Failure ofcooling system

Core hot spots

.overcurrent prot

.temperature sensors-> alarm or trip

Field thermal prot:.field winding.rotor body

Field thermal protection

Field overexcitation

Gen statorfault prot

Relaying scheme

Phase-fault protection

Ground-faultprotection

Gen rotorfield prot

Ground faultin the field circuit

Gen abnormaloperating conditions

Loss of field

Unbalancedcurrent

Loss of synchronism

overexcitation

motoring

overvoltage

Frequency abnormalities

Generator Protection [2] p. 314

For generators in the range of approximately 2 MW to 50 MW the following protection relays should be provided:

Overcurrent (51 V). Differential stator current

(87). Field failure (40). Field winding earth fault

(58). Reverse active power (32). Negative phase sequence

(46). Stator earth fault current

(51 G) and (64). Over terminal voltage, (59) Under terminal voltage, (27) Overfrequency, (81) Underfrequency, (81) 86 Hand-reset lockout

auxiliary relay.

Pengaman generator Pengaman thd arus lebih Pengaman thd teg lebih Pengaman thd beban tdk seimbang/Pengaman

arus urutan neg Pengaman kumparan stator Pengaman thd gangguan ke tanah dlm stator Pengaman thd temperatur lebih pd stator

Overcurrent relay

Differential Stator Current Relay (87) Differential current protection (87)

used for generators to detect internal winding faults, which

may develop between phase windings or between a phase and the steel core.

This type of protection is generally applied to high voltage machines above about 2 MW.

*transverse differential

12.2.8 Over Terminal Voltage (59)

The relay settings are usually set to operate at 115%, with a time delay between 0.5 and 10.0 seconds.

12.2.6 Negative Phase Sequence Relay (46) A negative phase sequence relay (46) protects a generator

against overheating of its rotor pole faces and damper bars.

This form of overheating is due to the presence of unbalanced stator currents, which create a negative phase sequence (NPS) flux in the air gap.

This flux rotates in the opposite direction to the rotor but at the same absolute speed. Hence the rotor poles and damper bars have double-frequency currents induced into them, which rapidly cause localized heating and eventually distortion of the rotor and slot damage.

Unbalanced Currents [4] p. 55 The ability of a generator to accommodate unbalanced currents is

specified by ANSI C50.12-1982 and ANSI C50.13-1989 in terms of negative-sequence current (I2).

This standard specifies the continuous I2 capability of a generator and the short time capability of a generator, specified in terms I2

2t, as shown in figure 4.5.2-1.

Unbalanced fault negative-sequence current capability is expressed in per unit of rated current and time in seconds.

1

[3]p. 254 Generators must meet minimal requirements for sustaining unbalance currents

without damage. These requirements are spelled out in ANSI C50.13 [5].

The protection against unbalanced currents is implemented by using overcurrent relays that measure negative-sequence components.

[4] p. 57

Types of protective elements used: direct acting devices are used e.g. fuses for

voltages up to about 33,000 volts or magnetic elements in low voltage moulded-case circuit breakers (MCCBs).

Radial type, etc