GB/T 25388.1-2021 English PDF (GB/T25388.1-2021)

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GB/T 25388.1-2021: Wind turbines generator system - Double-fed converter - Part 1: Technical condition
GB/T 25388.1-2021
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 27.180
F 11
GB/T 25388.1-2021
Replacing GB/T 25388.1-2010
Wind turbines generator system - Double-fed converter -
Part 1: Technical condition
ISSUED ON: MARCH 09, 2021
IMPLEMENTED ON: OCTOBER 01, 2021
Issued by: State Administration for Market Regulation;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword ... 3
1 Scope ... 6
2 Normative references ... 6
3 Terms and definitions ... 7
4 General requirements ... 13
4.1 Requirements for use conditions ... 13
4.2 Cabinets and components ... 15
4.3 Performance indicators ... 16
4.4 Fault protection ... 18
4.5 Security requirements ... 22
4.6 Electromagnetic compatibility ... 25
4.7 Operation and maintenance ... 27
4.8 Communication and monitoring ... 27
4.9 Protective performance ... 28
4.10 Requirements for vibration test ... 28
4.11 Requirements for high temperature test ... 28
4.12 Requirements for low temperature test ... 28
4.13 Requirements for constant damp heat test ... 28
5 Test methods ... 29
6 Inspection rules ... 29
6.1 Type test ... 29
6.2 Factory-exit test ... 29
7 Marking, packaging, storage, and transportation ... 31
7.1 Marking ... 31
7.2 Packaging ... 32
7.3 Storage ... 32
7.4 Transportation ... 33
Wind turbines generator system - Double-fed converter -
Part 1: Technical condition
1 Scope
This Part of GB/T 25388 specifies the relevant terms and definitions, general
requirements, calibration rules, and related product information of AC-DC-AC voltage
type converters for double-fed variable-speed constant-frequency wind turbines
generator systems (hereinafter referred to as “systems”).
This Part applies to AC-DC-AC voltage type converters for double-fed variable-speed
constant-frequency wind turbines generator systems, i.e., double-fed converters
(hereinafter referred to as “converters”).
2 Normative references
The following referenced documents are indispensable for the application of this
document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
GB/T 191 Packaging - Pictorial marking for handling of goods
GB/T 2423.56 Environmental testing - Part 2: Test methods - Test Fh: Vibration,
broadband random and guidance
GB/T 2900.53 Electrotechnical terminology - Wind turbine generator systems
GB/T 3797 Electrical control assemblies
GB/T 3859.1 Semiconductor converters - General requirements and line
commutated Converters - Part 1-1: Specification of basic requirements
GB/T 3859.2-2013 Semiconductor converters - General requirements and line
commutated converters - Part 1-2: Application guide
GB/T 4208 Degrees of protection provide by enclosure (IP code)
GB/T 4798.1 Classification of environmental conditions - Classification of groups
of environmental parameters and their severities - Part 1: Storage
GB/T 4798.2 Classification of environmental conditions - Classification of groups
of environmental parameters and their severities - Part 2: Transportation and
handling
factor of three-phase voltage unbalance
The degree of three-phase voltage unbalance in a three-phase power system. The root
mean square ratio of the negative sequence fundamental component to the positive
sequence fundamental component of the voltage, expressed as a percentage.
3.30
function of fault recorder
When a fault occurs in the converter, the converter has the function of automatically
storing the waveform at the fault time.
3.31
environmental temperature
When the converter is at a 60 mm horizontal surface, the average value of several points
equidistant between the sample and the test chamber wall, or the average value of
several points 1 m away from the sample, whichever is the smaller value.
3.32
mean time between failures
Under specified conditions and specified time, the average operating time between two
adjacent failures of the converter. It is calculated as formula (3):
where:
M - the MTBF time value, in hours (h);
T - the total effective operating time of the converter, in hours (h);
F - the total number of failures of the converter in this interval (events that cause the
system to shut down due to the converter are recorded as failures/events that cause
the system to shut down for maintenance due to the converter are recorded as
failures).
4 General requirements
4.1 Requirements for use conditions
4.1.1 Normal operating environment conditions
The grid voltage deviation at the common connection point on the low-voltage side of
the box-type transformer connected to the grid-side converter is within the range of -
10 % ~ +10 %, and the converter shall be able to operate continuously and normally.
4.1.2.3 Grid fault ride-through range
When the low-voltage side grid voltage of the step-up transformer connected to the
grid-side converter is within the range of 20 % ~ 90 % and 110 % ~ 130 % of the
nominal voltage, the converter shall be able to support voltage recovery by feeding
reactive current. The support time, the amplitude of the reactive current, and the
response time shall comply with the provisions of GB/T 36995.
NOTE: Voltage changes exceeding the above specified value in a short period of time may cause
work interruption or tripping. If continuous operation is required, it is agreed upon between the user
and supplier/manufacturer.
4.1.2.4 Grid voltage unbalance
When the grid voltage unbalance does not exceed 5 %, the converter shall be able to
operate normally on the grid. When the grid voltage unbalance is greater than 5 % and
less than 8 %, the converter can maintain on-grid operation.
4.1.2.5 Voltage total harmonic distortion rate, THDu
The waveform of the grid voltage shall be a sine wave. Under steady-state conditions,
the total harmonic distortion rate of the voltage is less than 5 %, and the converter shall
be able to operate normally. The harmonics of each order of the grid voltage shall meet
the requirements of GB/T 14549.
4.2 Cabinets and components
4.2.1 Cabinet design requirements
The design requirements of the converter cabinet are as follows:
a) The structure of the converter cabinet shall comply with the relevant provisions
of GB/T 20641;
b) The design of the converter cabinet shall meet the installation and maintenance
requirements in the tower and engine room; if necessary, corresponding vibration
reduction measures shall be taken;
c) The design of the converter cabinet shall meet the requirements for safety
grounding;
d) The converter enclosure, appearance, and surface shall be free of scratches and
deformations, and shall comply with the provisions of GB/T 3797.
4.2.2 Component requirements
The requirements for components used in the converter are as follows:
a) The components used in the converter shall comply with its own relevant
standards and the relevant provisions of GB/T 5226.1;
b) Anti-corrosion measures shall be taken into consideration for the metal parts of
the product. All parts shall be intact, and the appearance of the product shall be
free of scratches, damage, and deformation;
c) Product parts and components shall be installed correctly and firmly, and achieve
reliable mechanical and electrical connections;
d) The operation and adjustment parts of the cabinet, such as knobs, control switches,
transfer switches, buttons, etc., shall be flexible in operation, shall not be stuck,
loose, or have poor contact, and shall not have loosening or state change after
vibration.
4.2.3 Electrical connection requirements
The electrical connection requirements for the converter are as follows:
a) It shall ensure the correctness of each electrical connection; auxiliary components
such as relays, contactors, miniature circuit breakers, and electronic components
shall be confirmed to be in a qualified state before assembly;
b) The laying and connection of cables and conductors shall comply with the
provisions of GB/T 5226.1.
4.3 Performance indicators
4.3.1 Cut in current
When the converter performs grid connection control to the double-fed generator, the
cut in current shall not exceed one-third of the stator rated current peak value of the
double-fed generator.
4.3.2 Converter efficiency
Under the rated operating conditions, the converter efficiency shall not be less than
97 %.
4.3.3 Total power factor
The converter shall have the control function of adjusting the power factor of the system
between capacitive 0.95 and inductive 0.95.
The converter receives the reactive power dispatching instructions from the system
control system and shall have three reactive power adjustment methods: constant
voltage, constant reactive power, and constant power factor.
4.3.13 Reactive power control accuracy
Under different reactive power control modes, the reactive power accuracy of the
converter shall not be greater than 2.5 % of the rated reactive power.
4.3.14 Mean time between failures (MTBF)
The mean time between failures (MTBF) of the converter shall not be less than 18000
h.
NOTE: If there are special requirements for the mean time between failures of the converter, the
specific indicators shall be agreed between the user and supplier/manufacturer.
4.3.15 Grid current unbalance
Within the allowable range of grid voltage unbalance, the converter shall control the
maximum deviation of the three-phase current at the grid connection point of the system
to not exceed 5 % of the rated current of the system.
4.3.16 Noise
Under the rated operating conditions, the converter noise shall be less than 80 dB.
4.3.17 Common-mode voltage requirements
The converter shall be designed with a filter link or filter to match the common-mode
voltage tolerance level at the generator end.
NOTE: The specific tolerance voltage value is agreed upon between the user and
supplier/manufacturer.
4.3.18 Differential-mode voltage requirements
The converter shall be designed with a filter link or filter to match the differential-mode
voltage tolerance level at the generator end.
NOTE: The specific tolerance voltage value is agreed upon between the user and
supplier/manufacturer.
4.4 Fault protection
4.4.1 Fault type
When an abnormal situation occurs and the converter’s tolerable limit is exceeded, the
converter has the function of triggering fault protection to protect the safety of the
system and the converter. The converter fault protection functions include the following
two categories:
a) Class I fault protection: For serious faults. After this type of fault occurs, the
converter shall be able to trigger protection and implement an emergency
shutdown strategy. The converter uploads a Class I fault flag to the main control
and directly loads the load and shuts down at the same time. Class I fault
protection includes overcurrent protection, DC link voltage protection, power
device fault hardware protection, ground fault protection, phase loss protection,
phase sequence error protection, surge overvoltage protection, anti-islanding
protection, etc.
b) Class II fault protection: For general faults. After this type of fault occurs, the
converter uploads a Class II fault flag to the main control. At the same time, after
the converter continues to work for the set time, it implements a shutdown
strategy of slow load reduction on its own. Class II faults include overload
protection, power device over-temperature protection, generator under-
speed/over-speed protection, grid voltage unbalance protection, grid voltage
over-frequency/under-frequency protection, grid voltage over-voltage/under-
voltage protection, communication fault protection, etc.
NOTE: If there are special requirements, they shall be agreed upon between the user and
supplier/manufacturer.
4.4.2 Protection function
4.4.2.1 Instantaneous overcurrent protection (Class I fault protection)
When the operating current exceeds the instantaneous overcurrent protection threshold,
the converter shall be able to quickly start protection and shut down, including grid-
side overcurrent protection and generator-side overcurrent protection.
4.4.2.2 Short circuit protection (Class I fault protection)
When a short-circuit to ground or a multi-phase short-circuit fault occurs, the converter
shall be able to quickly start protection and shut down, including grid-side short-circuit
protection and generator-side short-circuit protection.
4.4.2.3 Phase loss protection (Class I fault protection)
The converter shall be equipped with phase loss protection. When a phase loss occurs
in the main circuit, the converter shall be able to quickly start protection, including grid-
side converter phase loss protection and generator-side converter phase loss protection.
4.4.2.4 Overvoltage protection (Class I fault protection)
When the operating voltage of the converter exceeds the maximum operating voltage
allowed by the converter, the converter shall be able to shut down for protection,
When the three-phase grid voltage unbalance factor exceeds the protection threshold,
the converter shall be able to trigger voltage unbalance protection according to the Class
II fault protection mechanism.
4.4.2.12 Grid over-frequency protection (Class II fault protection)
When the grid voltage frequency is higher than the protection threshold of the converter,
the converter shall be able to trigger grid over-frequency protection according to the
Class II fault protection mechanism.
4.4.2.13 Grid underfrequency protection (Class II fault protection)
When the grid voltage frequency is lower than the protection threshold of the converter,
the converter shall be able to trigger grid underfrequency protection according to the
Class II fault protection mechanism. The setting of the protection threshold shall meet
the requirements of the grid frequency range for normal operation of the co...