1-1: Test items: insulation resistance, absorption rate or polarization index of the stator winding
1-2: Test period: 1) 1 year or minor repair 2) before and after overhaul;
1-3: Test requirements: 1) The insulation resistance value is determined by yourself. If, under similar test conditions (temperature, humidity), the insulation resistance value drops below 1/3 of the normal value over the years, the reason should be identified. 2) The difference between the insulation resistance values of each phase or branch must not be greater than 100% of the minimum value 3) Absorption rate or polarization index: The absorption rate of the insulation in mica impregnated with asphalt and rolled shall not be inferior; greater than 1.3 or the polarization index should not be less than 1.3. It should not be less than 1.5; the absorption rate of epoxy powder mica insulation should not pas be less than 1.6 or the polarization index should not be less than 2.0, and the water-cooled stator should not be less than 1.3. the winding is stipulated by itself.
1-4: Test instructions: 1) For rated voltages above 1000V, use a 2500V megger, and the range is generally not less than 10000MΩ; 2) Use a special megger for water-cooled stator windings; 3) It is recommended to measure the polarization index for units of 200 MW and above.
1-5: Test equipment: HN2671 digital electrical megger; HN2520 pointer electric megger; HN2008 special megger for water-cooled generator
2-1: Test item: DC current of stator winding
2-2: Test period: 1) During the revision 2) After an output short circuit.
2-3: Test requirements: The DC resistance values of each phase or branch of the turbogenerator,after correcting the errors caused by different wire lengths, are different from each other and compared with the initial value. (factory or shed) When comparing measured values, the difference should not be more than 1.5% of the minimum value (1% for water turbine generators). If the requirements are exceeded, the reasons should be identified.
2-4: Test instructions: 1) In the cold When measured under normal conditions, the difference between the surface temperature of the winding and the ambient air temperature should not be higher than ± 3 ℃ 2) When the difference between the phases (or branches; ) of the turbogenerator and its relative variation over the years is greater than 1 %, it should be paid attention
2-5: Test equipment: HNZZ-3A DC resistance tester
3 -1: Test items: DC current test stator winding leakage and withstand voltage testCC
3- 2: Test period: 1) 1 year or during a minor repair 2) before and after a major repair; the winding.
3-3: Test requirements: 1) Test voltage: 3Un after replacing and repairing all stator windings; 2.5Un after partial replacement of stator windings and repair; 2.5 for those operating for 20 years; or less before overhaul, those which have been in service for 20 years or more before overhaul and which are directly connected to overhead lines are 2.5Un, those which have been in service for 20 years or more and which are not directly connected to airlines; lines before revision are 2.0Un to 2.5Un; those under minor repair and after overhaul are 2.0Un 2) Under the specified test voltage, the leakage current difference of each phase shall not be more than 100% of the minimum; value ; if the maximum leakage current is less than 20 μA, theDifference between phases should not change significantly from previous test results. 3) Leakage current Does not track; increases with time.
3-4: Testing Instructions: 1) It should be performed hot before removing contamination after shutdown. In standby mode, it can be carried out cold. Hydrogen-cooled generators should be used when the hydrogen purity after hydrogen charging is more than 96% or the hydrogen content after hydrogen discharge is less than 3%. Testing during the replacement process is strictly prohibited. 2) The test voltage is increased in steps of 0.5%; One per level, stay 1 minute at each stage; 3) When the leakage current increases significantly out of proportion with the voltage, attention should be paid to the analysis 4) During the test, the microammeter should be connected to the high voltage sidewe ; , and the surface of the output ring must be protected. If the water collection pipe of the water-cooled generator is insulated, the low-voltage shielding method should be used for wiring; If the water collection pipe is directly grounded, the test should be carried out without water and with the water pipe blown. The quality of the cooling water must be transparent and pure, without mechanical impurities. The conductivity when the water temperature is 20°C is: not more than 5.0×102μS/m for open water systems. for independent closed circulating water systems. p>3-5: Test equipment: YDJZ-30KVA-30KV DC leakage withstand voltage test device (including high voltage capacitor, DC milliammeter, voltage regulator console, water resistance, discharge rod )
4-1: Test item: stator winding AC withstand voltage test
4-2: Test period: 1) before overhaul 2) after the remwinding placement;
4 -3: Test requirements: 1) The test voltage after replacing and repairing all stator windings is as follows: ① The rated capacity is less than 10,000 kW, the rated voltage Un is greater than 36 V, the test voltage is 2Un+1000 V, but not less than 1500 V; ② The rated capacity is greater than or equal to 10,000 kW, the rated voltage If Un is less than 6000 V, the test voltage is 2.5 Un ③ If the rated capacity is greater than or equal to 10,000 kW and the nominal voltage; voltage Un is between 6000V and 18000V, test voltage is 2Un+3000V; ④ The rated capacity is greater than or equal to 10,000 kW and the rated voltage Un is greater than 18,000 V, the test voltage shall be treated according to special agreement 2; ) Before overhaul or after partial replacement of stator winding and repair, the test voltage is: ① For those in service for less than 20 years, the test voltage is 1.5Un ② For those who have been in service for more than 20 years; more than 20 years old and are directly connected to overhead lines, the test voltage is 1.5Un; ③ For those that have been operating for more than 20 years and are not directly connected to overhead lines, the test voltage is 1.3 Un -1.5Un; /p>
4-4: Testing Instructions: 1) Contamination must be removed after shutdown. Performed in the preheated state. When in a standby state, hydrogen-cooled generators must generally be tested with flowing water, and imported units must follow the manufacturer's regulations; 2) Water-cooled engines must generally be tested with flowing water, and imported units must follow the manufacturer's regulations; ) Where conditions permit, an ultra-low frequency (0.1 Hz) withstand voltage can be used and the test voltage maximal is 1.2 times the maximum value of the power frequency test voltage.
4-5: Test equipment: AC withstand voltage test device YDJ-3KVA-30KV HNCD-30; ultra-low frequency withstand voltage;Tester
5-1: Test item: Rotor winding insulation resistance
5-2: Test cycle: 1) During minor repair 2) Before and after cleaning the rotor; revision.
5-3: Test requirements: 1) The insulation resistance value is generally not less than 0.5MΩ at room temperature. 2) The insulation resistance value of the water-cooled rotor winding is generally not less than 5kΩ; at room temperature.
5-4: Testing Instructions: 1) Use a 1000V megger to measure. Water-cooled generators use meggers or other measuring instruments rated at 500 V and below. 2) For hidden pole motors below 300 MW, when the windingent of the stator has been dried but the rotor winding has not been dried, if the insulation resistance value of the rotor winding is less than 75. It is not less than 2KΩ at ℃ and its commissioning is authorized. 3) For hidden pole motors of 300MW and above, the electronic insulation value of the rotor winding is not less than 0.5MΩ at 10~30℃. .
5-5: Test equipment: HN2671 digital electrical megger; HN2520 pointer electric megger; HN2008 special megger for water-cooled generator
6-1: Test item: DC resistance of rotor winding
6-2: Test period: During overhaul
6-3: Test requirements: Comparison with the results measured for the first time (reset or revision), the difference generally does not exceed 2%
6-4: Testing Instructions: 1) Measure cold; 2) The exposed pole rotor winding must also measure the connection points between eachue magnetic pole coil
p>6-5: Test equipment: HNZZ-3A DC resistance rapid tester
7-1: Test item: Withstand voltage test Rotor Winding AC
7-2: Test period: 1) During the overhaul of the visible-pole rotor and after replacing the winding 2) After the hidden-pole rotor removes the ferrule, partially repairs the insulation in the slot and replaces the winding;
7-3: Test requirements: 1) Test voltage after replacement and repair of all pole rotor windings overt and hidden poles: 10Un for a nominal excitation voltage of 500 V and less, but not less than 1500 V + 4000 V for those with a nominal excitation voltage greater than 500 V; 2) Test voltage of the pole rotor manifested during overhaul and after partial replacement of windings and repairs: 5Un, but not less than 1000 V, not more than 2000 V 3) Test voltage of the rotor at poleshidden after partial repair of the insulation in the slot and after partial repair; replacement of windings and repairs: 5Un, but not more than 2000V Less than 1000V, not more than 2000V;
7-4: Testing Instructions: 1) When removing the hidden pole rotor shroud and repairing only the end insulation, a 2500V megger can be used to measure insulation resistance instead; the hidden pole rotor is at the end. For aluminum saddles, perform a winding tension test on the aluminum saddle after removing the ferrule. During the test, the rotor winding is connected to the shaft and a voltage of 2000 V is applied to the aluminum saddle. 3) The test voltage value during the whole rotor winding replacement process is as specified by the manufacturer.
7-5: Test equipment: AC withstand voltage test device YDJ-3KVA-30KV
8-1:Test item: Insulation resistance of equipment connected to the excitation circuit of generator and exciter (excluding generator rotor and exciter armature)
8 -2: Test cycle: 1) during a minor repair; 2) during major repairs.
8-3: Test requirements: The insulation resistance value should not be less than 0.5MΩ, otherwise the cause must be identified and eliminated
8 -4: Testing instructions: 1) For minor repairs, a 1000 V megger; 2) Use a 2500V megger during overhaul.
8-5: Test equipment: HN2671 digital electrical megger; HN2520 pointer electric megger;
9-1: Test items: AC withstand voltage test of the generator and exciter of the equipment connected to the excitation circuit (excluding the generator rotor and the exciter armature)
9-2: Test period: during overhaul
9-3: Test requirements: The test voltage is 1 KV
< p>9-4: Test instructions: A 2500 V megger can be used to measure the insulation resistance instead.9-5: Test equipment: HN2671 digital electrical megger; HN2520 Pointer Electric Megohm Meter;
10-1: Test item: stator core test
10-2: Test cycle: 1) Reassemble or replace or repair the silicon steel after chip 2) If necessary
10; -3: Test requirements: 1) When the magnetic density is 1T, the maximum tooth temperature increase is not more than 25K, the maximum tooth temperature difference is not more than 15 K and the unit loss is not greater than 1.3. multiplied by the reference value, determined by yourself at 1.4T. 2) See Annex A for the unit loss reference value.
10-4: Description of the test: 1) The duration of the continuous test is 90 min when the densmagnetic density is 1T, and the continuous test time is 45min when the magnetic density is 1.4T. When testing larger diameter hydrogenerators, attention should be paid to correcting errors caused by an uneven distribution of the magnetic flux density.
10-5: Test equipment: infrared thermal camera
11-1: Test item: Insulation resistance of generator and exciter bearings
11-2: Test period: During overhaul
11-3: Test requirements: 1) The bearings of the steam turbine generator set shall not be less than 0, 5MΩ 2) Each bearing of the thrust shaft of the vertical hydraulic generator; the whole must not be less than 100 MΩ; when the oil tank is filled with oil and the rotor is lifted, it is not less than 0.3MΩ 3) For all types of hydroelectric generators, where there are insulated guide bearings , each cpincushion; should not be less than 100MΩ before the oil tank is filled with oil.
11-4: Test Instructions: The bearing insulation of the turbine generator set is measured with a 100V megohmmeter after the oil pipe is installed.
11-5: Test equipment: HN2671 digital HN2520 pointer electric megger;
12-1: Test item: DC resistance of demagnetizing resistor (or self-synchronous resistor)
12 -2: Test cycle: During overhaul
12-3: Test requirements: Compared to the nameplate or originally measured data, the difference should not exceed 10%
< p>12-4: Test Description:12-5: Test Equipment: HNZZ-3A DC Rapid Resistance Tester
13-1: Test Item: Parallel Resistance of excitation switch
13-2: Test cycle: During overhaul
13-3: Test requirements: There is no significant difference fromort to initial value
13-4: Test instructions: The resistance value should be measured in sections
13-5: Test equipment: HNZZ DC rapid resistance tester -3A
14-1: Test item: AC impedance and rotor winding power loss
14-2: Test cycle: During overhaul
14-3: Test requirements: Impedance and power loss values are determined by yourself. There should be no significant change from previous years' values under the same testing conditions
14-5: Test Equipment: HNJL Generator Rotor AC Impedance Tester
15-1: Test Items: Thermometer Insulation Resistance and Error Inspection temperature
15-2: Test period: during overhaul
15-3: Test requirements: 1) The insulation resistance value is determined by you- same 2) The error of the thermometer indication value should not exceed the manufacturer's regulations;
p>
15-4: Testing instructions: 1) Use a 250 megger V and below 2) In addition to the integrated type, the thermometer also includes a water-cooled stator winding water outlet water thermometer;
15-5: Test equipment: HN2202 pointer electric megger
16-1: Test item: stat slot coil anti-halation layer potentialgold to ground
16-2: Test cycle: if necessary
16-3: Test requirements: not more than 10 V
16- 4: Test Instructions: 1) The potential of the temperature sensing element increases during operation and the slot wedge Measure when the anti-halation layer is loose or damaged 2) Apply the rated AC phase voltage value to the stator winding during the test and use a high internal resistance voltmeter to measure the voltage value of the winding surface to the ground; 3) Ultrasonic method can be used to detect slot discharge when conditions permit.
16-5: Test equipment: electrostatic voltmeter
17-1: Test item: Natural vibration frequency of turbine generator stator winding wire
17 -2: Test period: During overhaul
17-3: Test requirements: The natural frequency must not be less than ± 10% of the frequencye fundamental or multiplied frequency
17-4: Description of the test:
17-5: Test equipment: frequency test instrument
18-1: Test item: Measurement of DC voltage applied to the purse insulation at the end of the stator winding
18-2: Test period: 1) after production 2) during premiere; revision ; 3) time required.
18-3: Test requirements: 1) The DC test voltage value is One; 2) The measurement results should not be greater than the following values: A) The leakage current of the handbag insulated lead joint and the turbine side phase insulation joint is 20 μA, the drop value of voltage across the 100 MΩ resistor is 2000 V; B) The leakage current of the end connector (including the insulation of the water pipe cone) and the parallel block of the transition wire is 30 μA, and the voltage drop value on the resistor of 100 MΩ is 3000 V.
18-4: Test instructions: 1) This test is suitable for domestic hydro-hydrogen turbine generators of 200 MW and above 2) The test can be carried out under water supply conditions to detect leaks in stator seals; Defaults ; 3) Try to make it before production. Otherwise, testing should be arranged as soon as possible after production.
18-5: Test equipment: ZGF-60kV/2mA DC high voltage generator
19-1: Test item: shaft voltage
19-2: Test period: after overhaul
19-3: Test requirements: 1) When the bearing oil film of the turbogenerator is short-circuited, the voltage on the shafts at both ends of the rotor should generally be equal to the tension between the bearing and the frame; 2) The voltage between the main shaft of the steam turbine generator and the earth is generally less than 10V; 3) There are no regulations for the hydraulic generator;
19-4: Test description: Use an AC voltmeter with high internal resistance (at least 100 KΩ/V) when measuring
19-5: Test equipment : AC voltmeter
p> p>
20-1: Test item: Stator winding insulation aging identification
20-2: Cycle test: when the cumulative operating life is more than 20 years and the insulation breaks down frequently during operation or preventive testing
20-3: Testing requirements: see Annex A
20-4: Testing Instructions: When conditions permit, the stator winding can be tested for the first overhaul after the new machine is put into production to obtain the first results. Value
20-5: Test equipment:
21-1: Test item: No-load characteristic curve
21-2: Test cycle: 1) Review after; 2) After replacing the winding.
21-3: Testing requirements: 1) Against dataed by the manufacturer (or previously measured), they must be within the measurement error range 2) The highest value of the stator voltage at rated speed; a) Hydraulic generator is 1.5Un (limited not to exceed rated excitation current) b) Steam turbine generator is 1.3Un (1.1Un when equipped with a transformer) ; 3) For motors with insulation between turns, the maximum voltage lasts 5 minutes
21-4: Test instructions: 1) This test is not performed on synchronous capacitors without starting the motors; 2) The new machine; was not submitted when this test was carried out, a no-load characteristic curve test of 1.3 Un without a transformer must be carried out within one year during the general overhaul, the test can be carried out with the main transformer;
21-5: Test equipment:
22-1: Test item: Three-phase stable short circuit characteristic curve
22-2: Test cycle: 1) After replacing the winding; 2) When necessary.
22-3: Test requirements: Compared to the data provided by the manufacturer (or previously measured), the difference must be within the measurement error range.
22-4: Test description: 1) This test is not obligatory for synchronous capacitors without a starter; 2) When this test is not carried out when handing over a new machine, a three-phase stable short-circuit characteristic curve test without transformer must be carried out. carried out within one year.
22-5: Test equipment:
23-1: Test item: Demagnetization time constant when generator stator is open circuit
23-2: Test cycle: after replacing the excitation switch
23-3: Test requirements: There should be no significant difference in time constant compared to factory test or before replacement
23-4: Test instructions:
23-5: Test equipment:
24-1: Test item: Check phase order< /p>
24-2: Test cycle: when changing wiring
p>
24-3: Test requirements: must be consistent with the phase sequence of the electrical network
24-4: Test instructions:
24-5: Test equipment: phase sequence table
25-1: Test item: Temperature rise test
25-2: Test period: 1) After the stator and rotor windings are replaced; 2) After the cooling system has been improved; 3) Before a major overhaul; 4) When necessary;
25-3: Test requirements: must comply with the manufacturer's regulations.
25-4: Test instructions: If in doubt about the measured value of the built-in thermometer, measure average temperature with electricity Calibration method
For water-hydrogen-hydrogen cooled steam turbines, should the generator be charged with hydrogen before turning over? (The generator is not connected to the network)
Hydrogen is one of the gases with the lowest specific density, therefore the ventilation loss is low. The fan on the generator rotor in the turbine generator set has high mechanics. The efficiency and thermal conductivity of hydrogen are important. It can quickly dissipate generator heat and has high cooling efficiency. Hydrogen does not support combustion. The oxygen content of the generator is less than 2%, so the risk of fire is very low if the generator winding fails.
The generator of the turbogenerator group must therefore be cooled by hydrogen.
A generator whose stator and/or rotor are cooled by hydrogen. There are mainly all-hydrogen cooling and stator windings with coolinginternal water, the rotor winding and the stator core are cooled with hydrogen (water hydrogen), and the stator windings and rotor windings with internal water cooling, the core of the stator is cooled with hydrogen (hydrogen with water). ).
The windings and iron core of the generator generate heat during operation. In order to avoid burns due to excessive temperature, coolants include air, water, hydrogen, oil, freon, etc. , among which hydrogen is the most widely used because hydrogen has the advantages of good thermal conductivity (thermal conductivity is 8.4 times that of air), low density and diffusion fast. Hydrogen is used for cooling. It has a good cooling effect, is easy to transport, and can be recycled.
This is not necessary. If there is no network or conditions are not suitablefilled, and you want to check the vibration and exercise the auxiliary machine, you can run it completely as long as there is no excitation. current, the heat generation will not be very significant. Say no. In the hydrogen charging state, when the rotor rotates, the internal air flow is circular instead of dead. There are too many cases of starting without hydrogen charging and many power plants. I experienced this during the commissioning phase!