GB/T 7064-2017Specific requirements for cylindrical rotor synchronous machines (English PDF)

3.1 Synchronous generator

A large hidden-pole synchronous motor driven by a steam turbine or gas turbine that converts mechanical energy into electrical energy and sends it to the grid.

Note. The synchronous generator here is only applicable to this standard.

3.2 Synchronous camera

Connected to the grid, does not pass the shafting for electromechanical energy conversion, only transmits or absorbs reactive power to the grid by changing the excitation current

The rate of a large hidden pole synchronous motor.

Note. The sync camera here is only for this standard.

3.3 Mechanical start

The process in which the rotor speed is increased from zero or low speed (usually the crank speed) to the rated speed.

3.4 Car turning operation

A low-speed rotation that maintains the prime mover and the synchronous generator (or camera) rotor thermally balanced to avoid poor bending of the rotor.

4.1 General

Unless otherwise specified in this standard, synchronous generators driven by steam turbines or gas turbines, and synchronous cameras shall comply with GB/T 755.

This standard should be used as the basis for agreement between the supplier and the acquirer. If there are special requirements for specific products, it may be separately provided by the supplier and the buyer.

Agreed.

4.2 rated condition

4.2.1 Synchronous generator

The rated operating conditions of the generator are given by the following relevant data.

a) apparent power;

b) frequency;

c) voltage;

d) power factor;

e) primary cooling medium temperature (40 ° C, unless otherwise specified);

f) excitation voltage and excitation current;

Sometimes it also includes.

g) the altitude of the site;

h) hydrogen pressure;

i) For the purity range of hydrogen, see GB/T 755.

4.2.2 Synchronous camera

In addition to the apparent power and power factor, the rated condition of the camera is basically the same as that of the generator.

The rated apparent power is the maximum reactive output at rated voltage when the motor is over-excited, and a small amount of active power fed into the camera.

power.

The rated power factor is close to zero, mainly reflecting the maximum reactive power and loss compensated by the grid.

The range of the camera's reactive output can be determined by negotiation.

Note. The generator current (or camera) excitation current is regulated by reactive power. The rated excitation current and rated excitation voltage of the generator (or camera)

The rated condition of the generator (or camera).

4.3 Rated voltage

The rated voltage is determined by negotiation between the supplier and the buyer.

4.4 Power factor

The power factor is determined by negotiation between the supplier and the buyer. The standard rated power factor at the motor outlet is overexcited 0.8, 0.85 and 0.9.

Note 1. Other values can also be agreed upon. The lower the power factor, the larger the motor size.

Note 2. The rated power factor is the reactive power requirement when the over-excitation state at rated power is reflected.

Note 3. The generator design can take into account the ability to operate with rated power (MW) at a power factor of 0.95 (underexcited).

Because the grid compensates for the loss of the motor, the power factor of the synchronous camera may deviate from zero.

4.5 rated speed

For motors with a rated frequency of 50 Hz, the rated speed is 1500 r/min or 3000 r/min; for a rated frequency of 60 Hz

The machine is rated at 1800r/min or 3600r/min.

4.6 Voltage and frequency range

Synchronous generator (or camera) when the voltage deviation is ±5% under the rated power factor and the frequency deviation is ±2% (as shown in the shaded part of Figure 1)

Show), should be able to run continuously rated.

Table C.3 and Table C.4 temperature rise limits in Appendix C, or Table C.5 temperature limits, apply only to rated voltage and rated frequency.

If the operation needs to further expand the deviation range of voltage and frequency or the deviation from the nominal point, it should be negotiated between the supplier and the buyer.

Note 1. As the operating point deviates from the voltage and frequency ratings, the temperature rise or temperature will gradually increase. If the generator has a rated load on the boundary of the shaded part

Line, temperature rise or temperature increase of about 10K. If the generator has a rated power factor, voltage ± 5%, frequency 3-5%, as shown in the dotted line boundary shown in Figure 1,

The temperature rise will increase further, so to avoid the shortening of the service life of the generator due to temperature or temperature rise, the duration of operation outside the shaded area and

The frequency of occurrence should be limited and immediate corrective actions such as reduced output should be taken.

Note 2. It is unlikely that overvoltage and low frequency or low voltage and high frequency will occur simultaneously. The former will increase the temperature rise of the field winding. In the two cases shown in Figure 1.

The synchronous generator (or camera) and its transformer over-excitation or under-excitation are limited to within 5% of the operating quadrant. Excitation and under certain conditions

The margin of stability will decrease. When the operating frequency deviates from the nominal point, factors other than the generator become important and need to be considered. Such as steam turbine manufacturing

The plant will specify the allowable frequency deviation range and corresponding operating time, and the ability of the auxiliary machine to withstand overvoltage and high frequency should also be considered.

Note 3. During the phase induction test, the generator terminal voltage can be reduced to 92% in a short time.

Figure 1 Voltage and frequency limits

4.7 Direction of rotation and phase sequence

The direction of rotation (clockwise or counterclockwise) depends on the direction the reference end looks at the motor.

The reference end of the synchronous generator is the drive end. If there are two drive ends, the power end is the reference end in the direction of rotation.

The reference end of the synchronous camera is the opposite end of the excitation end.

Unless otherwise agreed, the direction of motor rotation should be clockwise from the reference end to the motor.

The direction of rotation should be marked on the motor or on the nameplate, and the time of the terminal voltage of the stator is represented by the letters U, V, W on the outlet end.

Order, U2, V2, W2 represent the phase tail.

The phase sequence of the synchronous generator (or camera) should be consistent with the phase sequence of the grid to be incorporated.

Note. The identification of the outlet end can be inconsistent with GB/T 1971.

4.8 Stator winding connection, output voltage

Unless otherwise specified, the stator windings are generally Y-shaped. The outlet end should be led to the outside of the frame, and the outlet layout should be confirmed with the purchaser.

The output voltage is defined as the stator winding line voltage.

4.9 Motor insulation

4.9.1 Insulation system, heat resistance grade

The insulation system consists of the insulation of the conductor insulation and the winding slots, the necessary distance to maintain the necessary distance, the end winding support and the insulation required for the connection.

Combination.

The insulation system shall be classified according to GB/T 11021 and the heat classification shall be 130 °C (Class B) or above.

The insulation system of the stator winding and the field winding shall have the ability to withstand the rated voltage for a long time. "Winding" includes coils and coils and out

All electrical connections between the line terminals.

Note. Refer to GB/T 17948.6 for insulation durability test.

4.9.2 Insulation resistance

4.9.2.1 Insulation resistance of stator winding to ground and phase

When the stator winding is at 40 °C, its insulation resistance to ground and phase should not be lower than the minimum recommended value of GB/T 20160.

R1min is 100 Mohm.

4.9.2.2 Polarization index R10min/R1min minimum recommended value

R10min/R1min>=2 (1)

In the formula.

Insulation resistance at R10min---10min;

Insulation resistance at R1min --1min.

When R1min >5000Mohm, the polarization index cannot fully reflect the insulation state and should not be used as an evaluation requirement.

See GB/T 20160 for insulation resistance and polarization index measurement methods.

4.9.2.3 Insulation resistance of the field winding

Insulation resistance of the field winding (excited winding directly cooled by water is measured before the insulated inlet pipe is installed), not small in the cold state (25 ° C)

At 1Mohm. The excitation winding directly cooled by water shall have an insulation resistance of not less than 2 kohm in the cold state (25 ° C) after the installation of the insulated water conduit.

4.9.2.4 Insulation resistance of the stator embedded thermometer

When measuring with a 250V megohmmeter in a cold state (25 ° C), the insulation resistance of the thermometer embedded in the stator should be not less than 1 Mohm.

4.9.2.5 Bearing insulation

Synchronous generator (or camera) excitation end bearing, exciter bearing or collector ring bearing between the bottom plate and the oil pipe, between the oil seal and the oil pipe,

Double insulation should be used between the inlet support and the bottom plate. When measured with a 1000V megger, the insulation resistance should be no less than 1Mohm.

4.9.3 Withstand voltage test

See the JB/T 6204 for the withstand voltage test method.

Before the AC withstand voltage test, the stator winding should be subjected to 3.5 UN in the manufacturing plant for 1 min DC withstand voltage test. Rated voltage

The 3.0UN DC withstand voltage test was performed for 24kV and above, and lasted for 1min.

The AC power frequency withstand voltage test lasted for 1 min and the test voltage was in accordance with Table C.1.

4.9.4 Corona test

The stator bar should not faint at 1.5 times the rated line voltage; the whole machine should be ignorant at the end of the stator winding at 1.0 times the rated line voltage.

Significant halo and continuous golden highlights.

4.9.5 High-voltage motor coil dielectric loss angle test method and limit

According to the provisions of JB/T 7608.

4.10 Prevention of shaft current

Appropriate measures should be taken to prevent harmful shaft currents and to ground the shaft well.

The synchronous generator (or camera) should be able to detect the resistance to ground insulation during operation.

Pulse shaft voltage caused by controlled rectification static excitation may cause oil film breakdown and damage bearing babbitt alloy, which should be effectively prevented.

The cause should be ascertained when the shaft voltage is greater than 20V.

4.11 Overspeed test

The rotor shall be subjected to an overspeed test at 1.2 times the rated speed for 2 minutes.

Note. The purpose of the overspeed test is to assess the mechanical integrity of the rotor and not to determine the operational capability of the motor. Whether the synchronous generator (or camera) in operation can bear

The ability to be subject to overspeed and frequency changes depends on the design of the motor, and the design is fully considered for various overspeed conditions of operation, such as sudden full operation during normal operation.

Rate overspeed caused by load shedding.

Any special needs must be determined in consultation with the manufacturer.

4.12 critical speed

In the frequency range specified in 4.6 or otherwise agreed, the unit shaft system shall not affect the synchronous generator due to the bad vibration caused by the critical speed.

(or adjust the camera) for safe operation.

4.13 output chart

The manufacturer shall provide a motor output diagram indicating the operating limits limited by temperature or temperature rise or by static stability. The figure is in the amount

Draw under constant voltage, rated frequency, and rated hydrogen pressure (if hydrogen cooling).

Figure 2 shows a typical output diagram. Its boundaries are limited by the following factors.

--- Curve A, indicating that the excitation current is running at the rated excitation current, and the temperature rise of the excitation winding is nearly constant;

--- Curve B, indicating that the stator winding temperature rise is nearly constant when operating at rated stator current;

--- Curve C, represents the limit of local heating by the stator end or by static stability or both.

In the case of agreement between the supplier and the demander, it is also possible to reduce the cooling temperature and exceed the rated voltage within the voltage range specified in 4.6.

A force diagram other than hydrogen pressure.

Synchronous camera does not have PQ requirements. If a generator with PQ output is used as a synchronous camera, the curve in the output chart

The range between the intersection of A and curve C and...