GB/T 50062-2008 (GB/T50062-2008)

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GB/T 50062-2008: PDF in English (GBT 50062-2008)

UDC
GB
National Standard
of the People's Republic of China
P GB/T 50062—2008
Code for Design of Relaying Protection and
Automatic Device of Electric Power Installations
Issued on December 15, 2008 Implemented on June 1, 2009
Jointly issued by the Ministry of Housing and Urban-Rural Construction
(MOHURC) and General Administration of Quality
Supervision, Inspection and Quarantine (AQSIQ)
Contents
1. General provisions ...1
2. General rules ...2
3. Generator protection ...3
4. Power transformer protection...7
5. 3~66kV power line protection...11
6. 110kV Protection of power circuit ...14
7. Bus bar protection ...15
8. Power condenser and reactor protection ...16
8.1 Power condenser protection ...16
8.2 Parallel reactor protection ...17
9. 3kV or above electric motor protection...19
10. Auto-reclose circuit breaker ...21
11. Automatic throw-in equipments of standby power and standby equipments ...23
12. Automatic low-frequency load-shedding devices ...24
13. Synchronous paralleling...25
14. Automatic Regulating Excitation and Automatic De-excitation ...26
14.1 Automatic regulating excitation ...26
14 2 Automatic de-excitation ...27
15. Secondary loop and relative equipment ...28
15.1 Secondary loop...28
15 2 Current transformer and potential transformer...29
15.3 DC power supply ...30
15.4 Anti-jamming measures ...30
Annex A Allowable Subtransient Current Times for Synchro Motor, Transformer in
Self-synchronizing and Asynchronous Switching-on ...32
Annex B Minimum Sensitivity Factor of Relay Protection ...33
11. General provisions
1.0.1 This code is formulated with a view to implementing the related national
technical-economic policies, to accomplishing state-of-the-art technology and economic
feasibility in the design of relaying protection and automatic device of electric power
installation.
1.0.2 This code is applicable to design of relaying protection and automatic device of electric
power installations like 3~110kV power circuit or equipment, power generator with
single-machine capacity of MW or below, 63MW·A or below power transformer.
1.0.3 For the design of relaying protection and automatic device of electric power installation,
not only the requirements stipulated in this code but also those in the current relevant ones
shall be complied with.
22. General rules
2.0.1 Electric equipment and circuit shall be installed with relaying protection and automatic
device for the reaction short-circuit fault and abnormal operation. The relaying protection and
automatic device shall be able to timely reflect the fault and abnormal operating condition of
equipment and circuit, and shall excise fault and restore the power supply as soon as possible.
2.0.2 The electric equipment and circuit shall be provided with main protection, back
protection and abnormal operation protection, and auxiliary protection may be added if
necessary.
2.0.3 Relaying protection and automatic device shall meet the requirements of reliability,
selectivity, sensitivity and quick-action, and they shall be in accordance with the following
requirements.
1 The relaying protection and automatic device shall be possessed of automatic on-line
measurement, blocking and device abnormity or fault alarm functions.
2 When there is cooperating requirement for adjacent equipment and circuit, the
sensitivity factor and actuation time of the up and down levels shall be interacted.
3 When protection equipment and circuit go out of order within the protection domain,
necessary sensitivity factor shall be possessed.
4 The protection device shall be able to excise short-circuit fault as early as possible.
When it requires fast excising short-circuit fault, protection device may be allowed to act
without selectivity, but it shall make use of automatic throw-in equipment of auto-reclose
circuit breaker or standby power and standby equipment, so as to shrink the power blackout
scope.
2.0.4 The sensitivity factor of the protection device shall be calculated according to
unfavorable normal operation mode and unfavorable fault type. If necessary, impact of
short-circuit current attenuation shall be taken into consideration. The minimum sensitivity
factors of various relaying protection shall comply with the requirements of Annex B of this
code.
33. Generator protection
3.0.1 The power generator with voltage of 3kV or above and capacity of 50MW or below
shall be installed with corresponding protection devices for the following faults and abnormal
operation modes.
1 Interphase short circuit of stator winding;
2 Stator winding grounding;
3 Turn-to-turn fault of stator winding;
4 External short circuit of power generator;
5 Overload of stator winding;
6 Overvoltage of stator winding;
7 Overload of rotor surface layer (loading);
8 Excitation circuit grounding;
9 Exciting current abnormally degression or disappearance;
10 Reverse power
3.0.2 The exit action of protection device may be classified into the following manners.
1 Halt. Disconnect the breaker of the power generator (or generator transformer), and
suppress the excitation. close up main throttle valve for steam turbine generator; and close up
water diversion leaf for hydraulic generator;
2 Parallel off excitation suppression. Disconnect the breaker of power generator (or
generator transformer), suppress excitation, reject load of steam (water) turbine;
3 Parallel off. Disconnect breaker of power generator (or generator transformer).
4 Narrow down the fault incidence;
5 Signal. Give out audible and visible alarm;
3.0.3 For the phase fault of generator stator winding and outgoing line, corresponding
protection device shall be installed to be used as the main protection of the power generator.
The protection device shall be acted until the halt, and shall be in accordance with the
following requirements.
1 For the 1MW or below power generator that operates independently. If outgoing line
lies in the neutral point side, overcurrent protection shall be installed in the neutral point side;
if no outgoing line is found in the neutral point side, low-voltage protection shall be installed
in the generator end.
2 1MW or below and other power generator or power generators parallel running with
the power system shall be installed with current quick-break protection in the generator end.
When the sensitivity of the current quick-break protection fails to meet the requirement,
longitudinal differential protection may be installed; as for the power generator without
outgoing line in the neutral point side, low voltage blocking and overflowing protection may
be installed.
3 For power generator of 1MW or above, longitudinal differential protection shall be
installed. For the generator transformer group, when breaker exists between the power
generator and the transformer, the power generator and transformer shall be installed with
longitudinal differential protection independently; when no breaker exists between the power
2 When the stator winding is star-shape line and the neutral point has no other than three
leading-out terminals, the 50MW power generator may also be installed with interturn
short-circuit protection.
Interturn short-circuit protection shall instantaneously act on halt.
3.0.6 The installed protection for the external phase fault of the power generator and backup
used for the main protection of the power generator shall be in accordance with the following
requirements.
1 The power generator with capacity of 1MW or below, or parallel runs with other power
generator or power system shall be installed wit...
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(Above excerpt was released on 2016-10-18, modified on 2021-06-07, translated/reviewed by: Wayne Zheng et al.)
Source: https://www.chinesestandard.net/PDF.aspx/GBT50062-2008