1 Scope
This standard is applicable to the magnetization tests for stator cores of turbine-type synchronous generators and hydraulic generators, for discriminating the generator stator core quality.
2 Normative References
The following standards contain provisions which, through reference in this text, constitute provisions of this standard. For dated reference, subsequent amendments to (excluding correction to), or revisions of, any of these publications do not apply. However, the parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the standards. For undated references, the latest edition of the normative document referred to applies.
GB/T 7064 Requirements for Turbine Type Synchronous Machine (GB/T 7064-2002, IEC 60034-341988, NEQ)
GB/T 8564 Specification for installation of hydraulic turbine generator units
3 Terms and Symbols
bv——Width of stator airway, in m;
B——Magnetic flux density at the stator core yoke in the test, in Tesla (T);
D1——Outer diameter of stator core, in m;
Di1——Inner diameter of stator core, in m;
f——Test power supply frequency, in Hz;
f1——Measured power supply frequency in the test, in Hz;
H——Magnetic field intensity at the stator yoke, in A/m;
hys——Stator core yoke height, in m;
hs——Stator slot depth, in m;
I——Magnet exciting coil current, in A;
——Stator core stacking coefficient;
KS——Power supply capacity coefficient;
lu——Clear length of stator core, in m;
l——Stator core length, in m;
m——Stator core yoke mass, in kg;
nv——Number of stator airways;
P——Measured power, in W;
P1——Calculated specific loss of stator core, in W/kg;
P10/50——Standard specific loss of stator core in the case of silicon sheet of 1.0T, 50Hz, in W/kg;
P14/50——Standard specific loss of stator core in the case of silicon sheet of 1.4T, 50Hz, in W/kg;
Q——Sectional area at the stator core yoke
ρ——Silicon sheet density, in kg/m3;
S——Capacity of test power supply, in kVA;
t——Test time, in min;
t0——Ambient temperature, in ℃;
t1——Temperature of the ith temperature measurement point in the test, in ℃;
U1——Magnet exciting coil voltage, in V;
U2——Measuring coil voltage, in V;
W1-——Magnet exciting coil turns;
W2——Measuring coil turns;
△tmax——Maximum temperature rise of core, after 45min (turbine-type synchronous generator) or 90min (hydraulic generator) of test from the beginning of the test, in kelvin (K);
△tmin——Minimum temperature rise of core, after 45min (turbine-type synchronous generator) or 90min (hydraulic generator) of test from the beginning of the test, in kelvin (K);
δt——The difference between the maximum and minimum temperature rise in the same position (stator tooth or slot) of the stator core, after 45min (turbine-type synchronous generator) or 90min (hydraulic generator) of test from the beginning of the test, namely, δt=△tmax-△tmin, in kelvin (K);
The symbols and units of the items in the following chapters of this standard shall be in accordance with this Chapter.
GB/T 20835-2007 The following standards are cited：
