1 Scope
This standard specifies the test preparation, test requirements, test method and core quality discrimination for magnetization test of generator stator core.
This standard is applicable to magnetization test of stator core for cylindrical rotor synchronous generators and hydro generators with the voltage grade of 6.3kV or above and is applicable to test of generator stator core assembly quality.
2 Normative References
The following referenced documents are indispensable for the application of this document. For dated references, only the editions cited apply. For undated references, the latest editions of the normative documents (include any amendment) apply.
GB/T 2521-2008 Cold-rolled Grain-oriented and Non-oriented Magnetic Steel Strip (Sheet)
GB/T 20160 Recommended Practice for Testing Insulation Resistance of Rotating Machinery
3 Symbols
For the purpose of this document, the following symbols apply.
bv——the width of stator ventilating duct, m;
B——the magnetic flux density of stator core yoke during the test, T;
D1——the outer diameter of stator core, m;
Di1——the inner diameter of stator core, m;
f——the frequency of test power supply, Hz;
f0——the reference frequency, 50Hz (for 50Hz generator) or 60Hz (for 60Hz generator), Hz;
f1——the measured power supply frequency during the test, Hz;
H——the magnetic field intensity of stator yoke, A/m;
hys——the height of stator core yoke, m;
hs——the stator slot depth, m;
I——the field coil current, A;
kFe——the stator core stacking factor;
KS——the power supply capacity factor;
lu——the clear length of stator core, m;
l——the length of stator core, m;
m——the mass of stator core yoke, kg;
nv——the number of stator ventilating ducts;
P——the measured power, W;
P1——The calculated specific loss of stator core during the test, W/kg;
Ps(1.0)——the standard specific loss of material for stator core silicon steel sheet under 1.0T and 50Hz or 60Hz, W/kg;
Ps(1.5)——the standard specific loss of material for stator core silicon steel sheet under 1.5T and 50Hz or 60Hz, W/kg;
Q——the sectional area of stator core yoke, m2;
ρ——the density of silicon steel sheet, kg/m3;
S——the capacity of test power supply, kVA;
t——the test time, min;
t0——the environment temperature, ℃;
ti——the temperature of i-th temperature measuring point during the test, ℃;
U1——the voltage of field coil, V;
U2——the voltage of measuring coil, V;
W1——the number of field coil turns;
W2——the number of measuring coil turns;
Δtmax——the maximum temperature rise of core from the beginning to the end of the test, K;
Δtmin——the minimum temperature rise of core from the beginning to the end of the test, K;
Δt——the difference between maximum temperature rise and minimum temperature rise of stator core at the same part (stator tooth or slot) from the beginning to the end of the test, i.e. Δt=Δtmax-Δtmin, K;
Δtmax1——the corrected maximum temperature rise of core, K;
Δtmax0——the measured maximum temperature rise of core, K;
Δt1——the corrected core temperature difference, K;
Δt0——the measured core temperature difference, K.
The symbols and units of quantities specified in this chapter apply to the following chapters herein.
Foreword I
1 Scope
2 Normative References
3 Symbols
4 Test Preparation
5 Test Requirements
6 Test Method
7 Core Quality Discrimination
Appendix A (Informative) Specific Loss of Stator Core
Appendix B (Normative) Test Data Correction
Appendix C (Informative) ELectromagnetic Core Imperfection Detector (ELCID)
