05 pengaman gen
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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