GB/T 20835-2016 English PDF (GB/T20835-2016)

GB/T 20835-2016: Guides for Magnetization Test of Generator Stator Core
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GB/T 20835-2016
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 29.160.20
K 20
Replacing GB/T 20835-2007
Guides for Magnetization
Test of Generator Stator Core
ISSUED ON. FEBRUARY 24, 2016
IMPLEMENTED ON. SEPTEMBER 1, 2016
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 Application Scope ... 5 
2 Normative References ... 5 
3 Symbols ... 5 
4 Test Preparation ... 7 
5 Test Requirements ... 9 
6 Test Method ... 10 
7 Core Quality Evaluation Criteria ... 13 
Annex A (Informative) Stator Core Specific Loss ... 14 
Annex B (Normative) Test Data Correction ... 15 
Annex C (Informative) Electromagnetic Core Imperfection Detector (ELCID)
... 16 
Foreword
This Standard was drafted in accordance with the rules given in GB/T 1.1-2009.
This Standard replaces GB/T 20835-2007, Guides for Magnetization Test of Generator
Stator Core. Compared with GB/T 20835-2007, the major changes of this Standard
are as follows.
-- it adds normative references, i.e. GB/T 2521, Cold-rolled Grain-oriented and Non-
oriented Electrical Steel Strip (Sheet), and GB/T 20160, Recommended Practice
for Testing Insulation Resistance of Rotating Machinery (Article 2);
-- it deletes normative references GB/T 7064, Specific Requirements for Cylindrical
Rotor Synchronous Machines, and GB/T 8564, Specification for Installation of
Hydraulic Turbine Generator Unit (see Article 2 of edition 2007);
-- it modifies the values of stator core stacking factor (see 4.1; 4.1 of edition 2007);
-- it adds the calculation formula of actual magnetic induction intensity B [see
Formula (7) of 6.4.1];
-- it adds the minimum limit of field density during core magnetization test (see 6.4.1);
-- it adds the test and its quality evaluation criteria of generator of rated frequency
60 Hz (see 6.4.2 and Article 7);
-- it modifies the conversion of stator core specific loss of cylindrical rotor
synchronous generator [see Formula (A.1) of Annex A and Formula (A.1) of
Annex A of edition 2007];
-- it adds Annex B (see Annex B);
-- it adds Annex C (see Annex C).
This Standard was proposed by China Electrical Equipment Industry Association.
This Standard shall be under the jurisdiction of China National Standardization
Technical Committee on Large Generators (SAC/TC 511).
The drafting organizations of this Standard. Harbin Institute of Large Electrical
Machinery, Dongfang Electric Corporation Dongfang Electric Machinery Co., Ltd.,
Shanghai Electric Power Station Equipment Co., Ltd., Shandong Qilu Electrical
Machinery Manufacture Co., Ltd., HydroChina Huadong Engineering Corporation,
China Three Gorges Corporation, State Grid Liaoning Province Electric Power Co., Ltd.
Electric Power Research Institute, Huadian Electric Power Research Institute Co., Ltd.,
Toshiba Hydro Power (Hangzhou) Co., Ltd., Zhejiang Fuchunjiang Hydropwer
Equipment Co, Ltd., Fujian Nandian Co., Ltd., Xiangtan Electric Manufacturing Group
Co., Ltd..
Guides for Magnetization
Test of Generator Stator Core
1 Application Scope
This Standard specifies the test preparation, test requirements, test method and core
quality evaluation criteria for magnetization test of generator stator core.
This Standard applies to magnetization test of cylindrical rotor synchronous generator
and water-turbine generator of voltage class 6.3 kV and above; it is used for the
inspection of assembly quality of generator stator core.
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 2521-2008, Cold-rolled Grain-oriented And Non-oriented Electrical Steel Strip
(Sheet)
GB/T 20160, Recommended Practice for Testing Insulation Resistance of Rotating
Machinery
3 Symbols
For the purposes of this document, the following symbols apply.
bv — stator vent width, in m;
B — stator core yoke field density during test, in T;
D1 — outer diameter of stator core, in m;
Dil — inner diameter of stator core, in m;
f — test power supply frequency, in Hz;
f0 — reference frequency, 50 Hz (for generator of 50 Hz) or 60 Hz (for generator of
60 Hz), in Hz;
f1 — measured power supply frequency during test, in Hz;
H — stator yoke magnetic field intensity, in A/m;
hys — stator core yoke height, in m;
hs — stator slot depth, in m;
I — excitation coil current, in A;
kFe — stator core stacking factor;
KS — power supply capacity factor;
lu — stator core net length, in m;
l — stator core length, in m;
m — stator core yoke mass, in kg;
nv — number of stator vents;
P — measured power, in W;
P1 — stator core specific loss calculated from test, in W/kg;
PS(1.0) — standard specific loss of stator core silicon steel sheet material under 1.0
T, 50 Hz or 60 Hz, in W/kg;
PS(1.5) — standard specific loss of stator core silicon steel sheet material under 1.5
T, 50 Hz or 60 Hz, in W/kg;
Q — stator core yoke sectional area, in m2;
ρ — silicon steel sheet density, in kg/m3;
S — test power supply capacity, in kVA;
t — test duration, in min;
t0 — environmental temperature, in °C;
ti — temperature of the i-th temperature measuring point during test, in °C;
U1 — excitation coil voltage, in V;
U2 — measuring coil voltage, in V;
W1 — number of turns of excitation coil;
W2 — number of turns of measuring coil;
Δtmax — maximum core temperature rise from the start to the end of test, in K;
Δtmin — minimum core temperature rise from the start to the end of test, in K;
wind stator core only.
4.5 Measuring coil voltage
Measuring coil voltage is estimated in accordance with Formula (6); the measuring
range of voltmeter is selected based on the estimation.
where,
W2 — number of measuring coil turns, generally 1 or 2.
4.6 Core temperature measurement
Measurement of core temperature with infrared thermography shall be given
precedence. If thermometric elements are embedded, thermocouples or thermometers
are arranged uniformly at the upper, middle and lower positions of outer and inner
circumferences of core; thermometers shall be placed in core yoke vent as far as
possible.
5 Test Requirements
5.1 Test power supply
Test power supply shall be an adequate alternating current power supply; its capacity
shall meet the power supply capacity value calculated in accordance with Formula (5).
5.2 Measuring apparatus
5.2.1 Electrical measuring apparatus
The accuracy of electrical measuring apparatus shall not be lower than grade 0.5;
power meter shall be lower power factor wattmeter. The measuring range of apparatus
shall be chosen as required by actual readings.
5.2.2 Instrument transformer
The accuracy of instrument transformer shall not be lower than grade 0.2.
5.2.3 Temperature measurement requirements
Temperature measurement can be carried out with infrared thermography, alcohol
thermometer or thermocouple thermometer or other instruments; it is not permissible
to use mercurial thermometer. The accuracy of temperature measurement of infrared
thermography shall not be greater than ± 2°C or measured value multiplied by ± 2%
6.5 Test records
Measure and record frequency, excitation coil terminal voltage, measuring coil terminal
voltage, excitation coil current and power, core temperature and environmental
temperature at least every 15 min. If possible, measure the temperature of core
embedded thermometer.
Calculate actual field intensity, power loss, unit iron loss, maximum core temperature
rise and maximum core temperature difference, based on the results of all
measurements.
6.6 Test precautions
Closely monitor stator core temperature rise, vibration and noise during test. In case
of smoking, local radiation and severe abnormal sound, cut off power supply and stop
test.
7 Core Quality Evaluation Criteria
7.1 Core maximum temperature rise limit
The maximum temperature rise limit of 50 Hz/60 Hz generator core is less than or
equal to 25 K under specified field intensity, after specified time in test.
7.2 Limit of temperature difference of the same position of core (stator tooth or slot)
The limit of temperature difference of the same position of 50 Hz/60 Hz generator
(stator tooth or slot) is less than or equal to 15 K under specified field intensity, after
specified time in test.
Annex C
(Informative)
Electromagnetic Core Imperfection Detector (ELCID)
(Electromagnetic Core Imperfection Detector-ELCID)
In case of a certain local failure of stator core, ELCID can be used for test.
In ELCID test, an annular coil is used to excite stator core in order to produce a
magnetic field and confirm the shor...
GB/T 20835-2016
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 29.160.20
K 20
Replacing GB/T 20835-2007
Guides for Magnetization
Test of Generator Stator Core
ISSUED ON. FEBRUARY 24, 2016
IMPLEMENTED ON. SEPTEMBER 1, 2016
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 Application Scope ... 5 
2 Normative References ... 5 
3 Symbols ... 5 
4 Test Preparation ... 7 
5 Test Requirements ... 9 
6 Test Method ... 10 
7 Core Quality Evaluation Criteria ... 13 
Annex A (Informative) Stator Core Specific Loss ... 14 
Annex B (Normative) Test Data Correction ... 15 
Annex C (Informative) Electromagnetic Core Imperfection Detector (ELCID)
... 16 
Foreword
This Standard was drafted in accordance with the rules given in GB/T 1.1-2009.
This Standard replaces GB/T 20835-2007, Guides for Magnetization Test of Generator
Stator Core. Compared with GB/T 20835-2007, the major changes of this Standard
are as follows.
-- it adds normative references, i.e. GB/T 2521, Cold-rolled Grain-oriented and Non-
oriented Electrical Steel Strip (Sheet), and GB/T 20160, Recommended Practice
for Testing Insulation Resistance of Rotating Machinery (Article 2);
-- it deletes normative references GB/T 7064, Specific Requirements for Cylindrical
Rotor Synchronous Machines, and GB/T 8564, Specification for Installation of
Hydraulic Turbine Generator Unit (see Article 2 of edition 2007);
-- it modifies the values of stator core stacking factor (see 4.1; 4.1 of edition 2007);
-- it adds the calculation formula of actual magnetic induction intensity B [see
Formula (7) of 6.4.1];
-- it adds the minimum limit of field density during core magnetization test (see 6.4.1);
-- it adds the test and its quality evaluation criteria of generator of rated frequency
60 Hz (see 6.4.2 and Article 7);
-- it modifies the conversion of stator core specific loss of cylindrical rotor
synchronous generator [see Formula (A.1) of Annex A and Formula (A.1) of
Annex A of edition 2007];
-- it adds Annex B (see Annex B);
-- it adds Annex C (see Annex C).
This Standard was proposed by China Electrical Equipment Industry Association.
This Standard shall be under the jurisdiction of China National Standardization
Technical Committee on Large Generators (SAC/TC 511).
The drafting organizations of this Standard. Harbin Institute of Large Electrical
Machinery, Dongfang Electric Corporation Dongfang Electric Machinery Co., Ltd.,
Shanghai Electric Power Station Equipment Co., Ltd., Shandong Qilu Electrical
Machinery Manufacture Co., Ltd., HydroChina Huadong Engineering Corporation,
China Three Gorges Corporation, State Grid Liaoning Province Electric Power Co., Ltd.
Electric Power Research Institute, Huadian Electric Power Research Institute Co., Ltd.,
Toshiba Hydro Power (Hangzhou) Co., Ltd., Zhejiang Fuchunjiang Hydropwer
Equipment Co, Ltd., Fujian Nandian Co., Ltd., Xiangtan Electric Manufacturing Group
Co., Ltd..
Guides for Magnetization
Test of Generator Stator Core
1 Application Scope
This Standard specifies the test preparation, test requirements, test method and core
quality evaluation criteria for magnetization test of generator stator core.
This Standard applies to magnetization test of cylindrical rotor synchronous generator
and water-turbine generator of voltage class 6.3 kV and above; it is used for the
inspection of assembly quality of generator stator core.
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 2521-2008, Cold-rolled Grain-oriented And Non-oriented Electrical Steel Strip
(Sheet)
GB/T 20160, Recommended Practice for Testing Insulation Resistance of Rotating
Machinery
3 Symbols
For the purposes of this document, the following symbols apply.
bv — stator vent width, in m;
B — stator core yoke field density during test, in T;
D1 — outer diameter of stator core, in m;
Dil — inner diameter of stator core, in m;
f — test power supply frequency, in Hz;
f0 — reference frequency, 50 Hz (for generator of 50 Hz) or 60 Hz (for generator of
60 Hz), in Hz;
f1 — measured power supply frequency during test, in Hz;
H — stator yoke magnetic field intensity, in A/m;
hys — stator core yoke height, in m;
hs — stator slot depth, in m;
I — excitation coil current, in A;
kFe — stator core stacking factor;
KS — power supply capacity factor;
lu — stator core net length, in m;
l — stator core length, in m;
m — stator core yoke mass, in kg;
nv — number of stator vents;
P — measured power, in W;
P1 — stator core specific loss calculated from test, in W/kg;
PS(1.0) —...