JB/T 7784-1995 Technical requirements for AC exciters for turbo-synchronous generators
Some standard content:
Mechanical Industry Standard of the People's Republic of China
Technical Conditions for AC Exciters for Turbine Synchronous Generators 1 Subject Content and Scope of Application
JB/T 778495
This standard specifies the type, technical requirements, test items, and marking, packaging, transportation, and storage requirements for AC exciters for turbine synchronous generators.
This standard applies to AC exciters for turbine synchronous generators. Any matters not specified in this standard shall comply with the relevant provisions of GB755-87 Basic Technical Requirements for Rotating Electrical Machines. 2 Reference standards
GB755--87 Basic technical requirements for rotating electrical machines GB/T7064--1996 Technical requirements for turbine-type synchronous generators GB7409--87 Basic technical conditions for excitation systems of large and medium-sized synchronous generators GB/T1029-93 Test methods for three-phase synchronous electrical machines GB11348.1·89
Measurement and evaluation of radial vibration of rotating shafts of rotating machinery Part 1: General provisions GB10069.1--88
Determination methods and limits of noise for rotating electrical machines Engineering determination methods for noise 3 Types
3.1 Classification
a. Stationary armature AC exciter;
b. Rotating armature AC exciter (brushless excitation). 3.2 Rated power
Rated power refers to the apparent power at the terminal together with the power factor (overexcitation) expressed in kVA, or kW. 3.3 Rated voltage
Rated voltage refers to the voltage between the motor terminals at rated power, expressed in V. 3.4 Rated speed
The speed of the AC exciter corresponding to the turbine synchronous generator at 50Hz is 1500r/min or 3000r/min, and the speed of the AC exciter corresponding to the turbine synchronous generator at 60Hz is 1800r/min or 3600r/min. 3.5 For brushless excitation, the rated rectifier voltage and maximum rectifier voltage of the rectifier ring are required, expressed in V, as well as the rated current and maximum rectifier current of the rectifier ring, expressed in A.
3.6 Driving type
The AC exciter is directly driven by the prime mover through the turbine synchronous generator. 3.7 Ventilation and cooling type
The AC exciter specified in this standard is generally cooled by air, and hydrogen cooling can also be used. The AC exciter should have an independent ventilation system, and can also be mixed with the auxiliary exciter or the main generator while ensuring good ventilation for each.
3.8 Bearing type
Approved by the Ministry of Machinery Industry of the People's Republic of China on October 9, 1995, 1008
Implemented on January 1, 1996
JB/T7784-95
AC exciter adopts seat bearing or end cover bearing, and can also be suspended on the shaft extension end of the main generator. 3.9 Excitation type
The excitation current of the AC exciter is supplied by the permanent magnet auxiliary magnet machine through the excitation regulator, or it can be supplied in other ways. 3.10 Direction of rotation
The direction of rotation of the AC exciter is determined by the turbine synchronous generator. 3.11 Motor insulation heat resistance grade
The armature winding, excitation winding and armature core insulation of the AC exciter adopt "B" grade or higher heat resistance grade insulation materials. 3.12 Armature winding
The armature winding of AC exciter is generally three-phase, connected in star or triangle, and brushless excitation can also use multi-phase winding. For static armature AC exciter, the number of outgoing wires can be 3, 4 or 6. 4 Technical requirements
4.1 Conditions of use
4.1.1 The altitude shall not exceed 1000m.
4.1.2 When the corresponding gas cooler inlet water temperature is 33C, the cooling gas inlet air temperature shall not exceed +40℃. When the AC exciter adopts hydrogen cooling, the purity and hydrogen pressure of nitrogen cooling shall be coordinated with the main generator hydrogen system. 4.1.3 The gas cooler inlet water temperature shall not exceed 33C. 4.1.4 When installed in the factory, the ambient temperature shall not be lower than 5C. Note: When the use conditions are inconsistent with this regulation, the ordering party and the manufacturer shall negotiate to resolve the issue. 4.2 AC exciters that need to be shipped for a long time or need to operate in a hot and humid climate should be equipped with heating devices. Whether other types of AC exciters are equipped with heating devices shall be resolved by negotiation between the ordering party and the manufacturer. 4.3 Thermometers should be buried between the upper and lower layers of the armature winding of the static armature type AC exciter for turbine synchronous generators. Two per phase; the core may not be buried with thermometers. Thermometers are not buried between the layers of the armature winding and the excitation winding of the brushless AC exciter. The motor should be equipped with an outlet temperature gauge. 4.4 When the AC exciter uses a seat bearing, a thermometer for measuring the bearing temperature or the oil outlet temperature should be installed, and an inspection window should be set on the oil outlet pipe.
4.5 Temperature limit
When the AC exciter is continuously running under rated conditions, the allowable temperature limit of each main part shall not exceed the value specified in Table 1. AC exciters with F-class insulation shall also be assessed as Class B. 4.6 When the AC exciter is running under rated conditions, the oil outlet temperature of the sliding bearing shall not exceed 65°C, and the bearing temperature shall not exceed 80°C. Table 1
Main parts
Armature winding
Excitation winding
.Joint of plate tube and radiator
Joint of diode and connecting line
Joint of fuse and radiator or
Joint of connecting line
Collector ring
Temperature measurement method
Brushless AC exciter
Resistance method
Resistance method
Overflow sheet method
Temperature sheet method
Overflow sheet method
Stationary armature AC excitation Machine
Buried between the upper and lower layers in the slot
Thermometer method
Resistance method
Thermometer method
Allowable humidity rise K when the cooling air humidity is
40℃
80(B grade)
80(B grade)
Allowable temperature C when the cooling air temperature is
4.7When the excitation voltage and current of the turbine synchronous generator do not exceed 1.1 times of its rated excitation voltage and current, the AC exciter should be able to ensure continuous operation.
JB/T7784—95
4.8The load peak voltage multiple of the AC exciter for turbine synchronous generators of 100MW and above is generally not less than 1.8, and the others are generally not less than 1.6. If there are special requirements, the manufacturer and the user shall negotiate and determine. 4.9 The AC exciter is allowed to last for 20 seconds. 4.10 Short-time voltage rise test
If the excitation voltage exceeds 130% of the rated voltage, the no-load test voltage should be tested at the limit voltage during forced excitation. The test duration is 1 minute when there is a turn-to-turn interval and instantaneous when there is no turn-to-turn interval. 4.11 AC exciter voltage response ratio
The voltage response ratio of the AC exciter used for turbine synchronous generators of 100MW and above is generally not less than 2 units/second, and for others it is 0.5~1 unit/second. If there are special requirements, it shall be determined by the manufacturer and the user through consultation. 4.12
AC exciter withstand voltage test
Motor parts
AC exciter frame winding
AC exciter excitation winding
Rotating rectifier ring electrical components
Working test voltage (effective value, lasting 1min) For the rated excitation voltage of the main generator of 350V and below, 10 times the rated excitation voltage, minimum 1500V For the rated excitation voltage of the main generator of more than 350V: 2 times the rated excitation voltage + 2800V 10 times the rated excitation voltage of the AC exciter, minimum 1500V For the rated excitation voltage of the main generator of 350V and below: 10 times the rated excitation voltage, minimum 1500V For the rated excitation voltage of the main generator of more than 350V: 2 times the rated excitation voltage + 2800V, the withstand voltage test values of the windings and electrical components of the AC exciter shall be as specified in Table 2. 4.12.2 The brushless excitation rectifier and AC excitation machine armature can be subjected to withstand voltage test together, but they must be conducted separately from the turbine synchronous generator excitation field winding, and the two terminals of the rectifier must be short-circuited in advance during the test. 4.13 The brushless excitation rectifier, fuse and other rotating devices of the turbine synchronous generator should be subjected to overspeed test at the same time as the armature. The resistance of each fuse and the reverse leakage current of each rectifier should not change significantly before and after overspeed. 4.14 80% of the reverse peak voltage of each rectifier bridge arm diode of the brushless excitation should be greater than 4 times the rated excitation voltage of the turbine synchronous generator.
4.15 For a three-phase brushless exciter, when the number of parallel branches is equal to or greater than 4 and one of the branches is out of operation, the excitation current required for all operating conditions including strong excitation shall be guaranteed. When two branches are out of operation, the excitation current required for the turbine synchronous generator under rated operating conditions shall be guaranteed: when the number of parallel branches is less than 4 and one branch is out of operation, the excitation current required for the turbine synchronous generator under rated operating conditions shall be guaranteed. If more branches are out of operation, the machine shall be shut down immediately. When the number of parallel branches of a three-phase machine is 1 and one branch is out of operation, the machine shall be shut down. For a multi-phase brushless exciter, when one phase is out of operation, the excitation current required for all operating conditions including strong excitation shall be guaranteed. When two phases are out of operation, the machine shall be shut down.
4.16 The excitation current of a brushless excitation turbine synchronous generator shall have necessary detection signals or provide adjustment characteristic curves of equivalent load resistance of the exciter. When the rectifier bridge arm adopts a parallel rectifier, necessary rotary fuse detection signals shall also be provided. The rotor winding of the turbine synchronous generator shall have a grounding alarm device. Special requirements shall be determined by negotiation between the user and the manufacturer. 4.17 Vibration value
4.17.1 Before leaving the factory, the rotor shall be run alone at rated speed to assess vibration. The vibration of the shaft system of the machine assembly shall be assessed at rated state on site. The measurement method and requirements of shaft vibration are shown in GB11348.1. For generator sets with power below 200MW, only the vibration of the bearing seat shall be measured; for units with power of 200MW and above, the vibration of the bearing seat and the shaft shall be measured at the same time. Table 3 shows the limit values for measuring bearing seat vibration, Table 4 shows the limit values for measuring relative displacement of shaft vibration, and Table 5 shows the limit values for measuring absolute displacement of shaft vibration. Shaft displacement assessment can be based on Table 4 or Table 5. The vibration test value of the new machine shall be within the A range when leaving the factory. The vibration during speed increase or decrease, over critical speed or overspeed shall not exceed the C range. The equipment with vibration values within the A range can be considered to be good and can be operated without restriction, and the equipment with perturbation values within the B range can be accepted for long-term operation. When the vibration value is within the C range, the alarm starts, and maintenance should be arranged in advance. Generally, the machine can still run for a limited period of time until there is a suitable opportunity for maintenance. If the vibration value exceeds C, it should trip instantly. When there is no thrust bearing in the axial direction, the axial vibration of the shaft is not evaluated. 1010
JB/T7784—95
Measure the limit value of bearing seat vibration (peak-to-peak value) in vertical and horizontal directions
Speed r/min
Measure the limit value of relative displacement of shaft vibration (peak-to-peak value) in vertical and horizontal directions
Measure the limit value of absolute displacement of shaft vibration (peak-to-peak value) in vertical and horizontal directions
The natural frequency of machine base vibration should avoid the fundamental frequency and the frequency multiple by more than 10%. .The vibration of the machine base shall not exceed 20μm (peak-to-peak value). 4.17.2
3 Critical speed
Within the specified rated speed variation range of the turbine synchronous generator, the critical speed of the AC exciter will not cause adverse vibrations and affect the safe operation of the unit.
4.19 Overspeed
The AC exciter should be subjected to a cold overspeed test at a speed of 120% of the rated speed. The corresponding frequency is 50Hz for the AC exciter used in the main generator. The test lasts for 2 minutes. The corresponding frequency is 60Hz for the AC exciter used in the main generator. The test lasts for 1 minute. No damage or harmful deformation occurs. The structural design of the AC exciter should consider the ability to withstand a sudden short circuit at no load under the outlet three-phase strong excitation voltage without harmful deformation. 4.20
Regulations on the number of starts
Generally, the rotor should be able to withstand a number of starts of not less than 3000 times within its service life. The AC exciter rotor of the turbine synchronous generator in two-shift peak-shift operation should be able to withstand no less than 10,000 starts within its service life.
2 Allowable deviation of DC resistance of each phase of armature winding When the AC exciter pole winding is cold, the difference in DC resistance between any two phases should not exceed 2% of its minimum value after excluding the error caused by different lead lengths.
4.23 The sinusoidal distortion rate of the AC exciter line voltage waveform should not exceed the following values: 5% for rated power above 300kVA; 10% for rated power 300kVA and below. 4.24
Insulation resistance
JB/T7784-95
4.24.1 When the armature winding of the AC exciter is close to the operating temperature after drying, the insulation resistance to ground and between phases measured with a 1000V ohmmeter shall not be less than the value obtained by the following formula: U
R=1000+P/100
Wherein; R---insulation resistance value, Ma;
--armature winding rated voltage, V;
P..motor rated power, kVA.
4.24.2 The insulation resistance of the excitation winding of the AC exciter, measured with a 500V megohmmeter in the cold state, shall not be less than 0.5Mα. 4.24.3
The insulation resistance value of the embedded thermometer of the armature of the AC exciter shall not be less than 4.24.4 The insulation resistance value between the bearing of the AC exciter and the base plate and the oil pipe shall not be less than 1Mn when measured with a 1000V megohmmeter. 4.24.5 The insulation resistance of the brush holder of the AC exciter to the ground shall not be less than 0.5Mα when measured with a 500V megohmmeter. 4.25 The noise of the AC exciter shall not be greater than 92dB(A). The noise engineering measurement method shall comply with GB10069.1. 5 Test items of AC exciter
5.1 Inspection test items of AC exciter
Measurement of the insulation resistance of the winding to the casing and between the windings. 5.1.2 Measurement of the DC resistance of the winding in the actual cold state. 5.1.3 Overspeed test.
5.1.4 Determination of vibration.
5.1.5 Determination of no-load characteristics.
Short-time voltage increase test.
Determination of steady-state short-circuit characteristics and heating test at 150% rated current for 2 minutes. Sealing status inspection and hydrogen leakage measurement (for hydrogen-cooled AC exciter). Withstand voltage test.
Air gap measurement.
Measurement of leakage current before and after overspeed of non-destructive excitation rectifier tube. Determination of AC impedance of excitation winding at different speeds. Measurement of bearing inlet and outlet oil temperature and bearing shell temperature. 5.2 Type test items of AC exciter
In addition to all the above inspection and test items, the following items are added: 5.2.1 Determination of the regulation characteristics of the AC exciter with the load resistance of the brushless excitation rectifier ring equivalent to the rotor resistance value of the main generator. 5.2.1.1 Determination of the excitation current and voltage of the AC exciter corresponding to the rated data of the AC exciter. 5.2.1.2 Determination of excitation current and voltage of AC exciter when main generator is no-load and rated voltage. Determination of excitation current and voltage of AC exciter when main generator is rated load. 5.2.1.3
5.2.1.4 Determination of excitation current and voltage of AC exciter when main generator is strongly excited. 5.2.2 Temperature rise test.
5.2.3 Determination of loss and efficiency.
5.2.4 Determination of sinusoidal distortion rate of voltage waveform. 5.2.5
Determination of AC exciter parameters and time constant. Determination of voltage response ratio and peak voltage of AC exciter (complete set test of main exciter, auxiliary exciter and AVR, see GB7409-87 for methods).
Sudden short circuit test when three-phase no-load and strongly excited voltage (generally this test is not performed, but it is performed after negotiation when the user requires it). Monthly non-operating speed
Noise measurement.
5.3 Acceptance test items for AC exciter
JB/T7784-95
Measurement of insulation resistance between winding and casing. Measurement of DC resistance of winding in actual cold state. Measurement of no-load characteristics and steady-state short-circuit characteristics (stationary armature AC exciter). Withstand voltage test, the test voltage is 80% of the factory test value, lasting 1min. Short-term voltage increase pattern.
Vibration measurement.
Air gap measurement.
Measurement of bearing inlet and outlet oil temperature and bearing shell temperature. Measurement of inlet and outlet air temperature.
Warranty period
If the user uses and stores the motor correctly according to the manufacturer's product manual, the manufacturer shall guarantee that the motor can operate well within one year of use and no more than two years from the date of shipment from the manufacturer. If the motor is damaged or fails to work properly due to poor manufacturing quality within the specified time, the manufacturer shall repair (or replace) the parts (or motor) for the user free of charge. 7 Product certificate
The manufacturer's product quality management department shall make an inspection conclusion when the motor leaves the factory and fill in the product certificate. The product certificate and the motor are equipped with spare parts
See Appendix A (Supplement).
9 Random drawings and technical documents
See Appendix B (Supplement).
10 Marking, packaging, transportation and storage
The nameplate of the AC exciter shall include the following contents: 10.1.1
Motor name.
Manufacturer name.
Motor model.
Rated power (kVA) or (kW) and rated power factor. Rated voltage (V).
Rated current (A).
Rated excitation voltage (V).
Rated excitation current (A).
Rated speed (r/min). www.bzxz.net
Frequency (Hz).
Wiring method.
Insulation grade, use grade.
Standard number.
Weight.
Manufacturer product number.
Year and month of production.
JB/T7784-·95
The nameplate of the AC exciter cooler shall include the following information: 10.2.1
Product name.
Manufacturer name.
Cooler model.
Rated power (kW).
Rated cooling water temperature (C).
Water pressure drop (Pa).
Water consumption (m*/h).
Maximum working pressure (Pa).
Air volume (m*/s).
Air pressure drop (Pa),
Standard number.
Weight.
Manufacturer production number.
Production year and month.
3Packing and transportation
When the AC exciter is shipped from the manufacturer, it should be properly packaged and well fixed to prevent slippage and damage during transportation. The following marks should be on the packaging box:
Product name and model.
Gross weight and net weight (kg).
10.3.3 Manufacturer's name and address,
10.3.4 Receiving unit and destination.
10.3.5 Precautions (such as adding "handle with care", "prevent moisture", "prevent silicon contact", etc.). 10.4 Anti-rust, anti-freeze and storage temperature
The surface of the AC exciter rotor should be coated with anti-rust oil or paint to prevent rust. The water in the gas cooler should be drained clean, and its inlet and outlet must be properly sealed. The minimum storage temperature of the AC exciter is 5C. 10.5 According to different packaging needs, there are two different levels of packaging: general packaging and sealed packaging. When transporting for a long time by sea and in hot and humid climates, the stator and rotor should be sealed or have moisture-proof measures, such as using insulated gas. 1014
JB/T 7784--95
Spare parts and spare parts
(Supplementary parts)
AC exciter armature coil half-group type 4 upper layers, 2 lower layers: 3 pull-type coils (spare parts are not provided for the whole motor). 2 AC exciter brush boxes, 1 brush. 1 AC exciter bearing.
1 AC exciter gas cooler.
1/4 set of rotating diodes with positive and negative polarity
1/2 set of rotating fuses.
Appendix B
Random drawings and technical documents
(Supplementary parts)
Product certificate.
Scope of supply.
Packing list
Product manual.
Technical data.
Product drawings.
General assembly.
Armature assembly.
Magnetic pole assembly.
Armature coil.
Magnetic pole coil.
Bearing processing drawing.
Temperature measuring device layout drawing.
Cooler installation drawing.
Assembly drawing of rotating rectifier ring.
Installation drawing.
Seat plate drawing.
Additional remarks:
This standard is proposed and managed by the Steam Turbine Generator Sub-Technical Committee of the National Technical Committee for Standardization of Rotating Electrical Machines. This standard is drafted by Beijing Heavy Electric Machine Factory. The main drafters of this standard are Hao Weikang, Shen Liangwei and Dai Wenying. 1015
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