GB/T 7409.3-2007 English PDF (GBT7409.3-2007)

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GB/T 7409.3-2007: Excitation system for synchronous electrical machines -- Technical requirements of excitation system for large and medium synchronous generators
GB/T 7409.3-2007
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 29.160.20
K21
Replacing GB/T 7409.3-1997
Excitation System for Synchronous Electrical Machines -
Technical Requirements of Excitation System for Large and
Medium Synchronous Generators
ISSUED ON: JANUARY 16, 2007
IMPLEMENTED ON: AUGUST 1, 2007
Issued by:
General Administration of Quality Supervision, Inspection and
Quarantine of the People’s Republic of China;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative References ... 4
3 Terms and Definitions ... 5
4 Operating Conditions ... 6
5 Basic Performance ... 6
6 Tests ... 11
7 Marking, Packaging, Transportation and Storage ... 12
8 Product Quality Assurance Period ... 14
9 User's Special Requirements ... 14
Excitation System for Synchronous Electrical Machines -
Technical Requirements of Excitation System for Large and
Medium Synchronous Generators
1 Scope
1.1 This Part specifies the technical requirements, test items, marking and packing
of the excitation systems for synchronous electrical machines and phase modifiers and
it applies to the excitation systems for those 10MW and above hydraulic generators,
50MW and above turbine-type synchronous electrical machines and phase modifiers
that are connected with power system. The excitation systems for generator motors
also may be used by making reference thereof.
1.2 This Part only applies to the excitation systems of the following types:
1.2.1 Excitation system with AC exciter
a) AC exciter with stationary rectifier;
b) AC exciter with rotating rectifier (brushless excitation system).
1.2.2 Static excitation system
a) Potential source static excitation system;
b) Compound source static excitation system.
2 Normative References
The following normative documents contain provisions which, through reference in
this Part, constitute provisions of this Part. For dated reference, subsequent
amendments to (excluding correction to), or revisions of, any of these publications do
not apply. However, the parties whose enter into agreement according to these
specifications are encouraged to research whether the latest editions of these
references are applied or not. For undated references, the latest editions of the
normative documents are applicable to this Part.
GB 755 "Rotating Electrical Machines-Rating and Performance" (GB 755-2000, idt
IEC 60034-1:1996)
GB 1094 (all parts) "Power Transformers" (GB 1094.1-1996, eqv IEC 60076-1:1993;
GB 1094.2-1996, eqv IEC 60072-2:1993; GB 1094.3-2003, IEC 60076-3: 2000,
4 Operating Conditions
4.1 Ambient temperature
The maximum ambient temperature shall not exceed +40℃ and the mean temperature
within 24h shall not exceed +35℃ or less than -5℃. The temperature variation ratio
of working environment shall not be larger than 5℃/h. (rectifiers adopt the water
cooling type, and its minimum temperature is +5℃).
4.2 Relative ambient air humidity
The maximum mean average relative humidity of the most humid month at the
operating site shall not exceed 90%, and the mean monthly minimum temperature of
this month shall not be larger than 25℃.
4.3 Gaseous contamination
No conductive or explosive dust, corroding metal or gas or steam destroying the
insulation exit at the operating site.
4.4 Oscillation
Oscillation condition allowed at the operating site: when the oscillation frequency
scope is 10Hz~150Hz, the oscillating acceleration shall not be larger than 5m/s2.
4.5 Altitude
The absolute altitude at the operating and application site shall not exceed 1000m.
When the altitude is larger than 1000m, the influence of the altitude increase on
excitation system shall be taken into account.
4.6 Station service condition
The voltage deviation of the DC and AC supplies for the power plant service shall not
exceed +10%~-15% of the rated value, the frequency deviation of AC supply shall not
exceed +4%~-6%.
4.7 Installation inclination
For the equipment installed vertically, the installation inclination shall not greater than
5%.
5 Basic Performance
5.1 The excitation system shall meet the relevant requirements of GB 755.
5.2 When the excitation voltage and current of synchronous electrical machine are
not greater than 1.1 times of the rated values, the excitation system shall ensure that it
may continuously operated.
5.3 The excitation ceiling voltage ratio shall be determined according to the network
condition and the status of the generator in the network:
a) Generally is 1.8 times for the 100MW and above turbine generators;
b) Generally is 2 times for the 50MW and above hydraulic generators;
c) Generally is 1.6 times for other types.
For the potential source static excitation system with its excitation source provided
from the generator terminals, its excitation ceiling voltage ratio shall be calculated
according to 80% of the generator rated voltage.
5.4 The excitation system ceiling current shall not exceed 2 times of the rated
excitation current, and the permissible duration shall not be less than 10s.
5.5 The excitation system nominal response is specified as follows:
a) The excitation system nominal response of the 50MW and above hydraulic
generators and 100MW and above turbine generators shall not be less than 2
times of the rated excitation voltage per second;
b) Excitation system nominal response of other types shall not be less than 1
times of the rated excitation voltage per second.
5.6 The automatic voltage regulation function of excitation system shall be able to
guarantee its steady and smooth regulation within 70%~110% of the rated no-load
voltage of generator.
5.7 The manual excitation regulation function of excitation system shall be able to
guarantee smoothly regulating the excitation current of synchronous electrical
machine within a scope from 20% of its no-load excitation current to 110% of its
rated excitation current.
5.8 When the synchronous electrical machine operates at no load, the changing
speed of the machine voltage caused by the variations in the given values of automatic
voltage regulator and manual controller shall be within 0.3%~1% of the rated voltage
of the machine.
5.9 The excitation system shall guarantee the setting range of the reactive current
compensative ratio (idle current compensation) of synchronous generator being no
less than ±15%.
5.10 The excitation system shall guarantee the static potential difference rate of the
5.18 The excitation system shall be with excitation suppression function and be able
to de-excite reliably under normal operating conditions or under the following
abnormal conditions:
a) The excitation current of the generator that operates in systems shall not
exceed the rated value, and the stator circuit shall be of short circuit externally
or internally.
b) Generator no-load abnormal forcing (the relay protection acts).
5.19 The redundancy of the power rectifiers in excitation system may be set
according to that the rest branch circuits still can meet all the operation condition
requirements of generator after one among the parallel branches of all the power
rectifiers is out of service, and the current equalization coefficient of the power
rectifiers shall not be less than 0.85.
5.20 The following factors shall be taken into account when selecting the excitation
transformers:
a) ...