DL/T 2020-2019Code of operation and maintenance for Pelton turbine (English PDF)

4.1 General rules

4.1.1 The technical conditions and requirements of bucket-type turbines should meet the requirements of relevant parts of GB/T 15468; turbine automation components and systems it should meet the requirements of GB/T 11805; the turbine regulating system should meet the requirements of relevant parts of GB/T 9652.1, DL/T 563, and DL/T 792;

The inlet ball valve at the front end of the turbine shall meet the requirements of GB/T 14478.

4.1.2 Operators should receive technical training and master the relevant skills of bucket turbine operation.

4.1.3 There should be an operation management system for equipment patrol inspection, regular test and rotation, defect management, etc.

4.1.4 The operation safety management of the water turbine shall comply with the relevant safety work regulations of GB 26164.1 and GB 26860.

4.1.5 The power station shall compile on-site operation regulations according to its own characteristics and establish necessary operation records. According to the collected operation data, regular Analyze the running state of the turbine.

4.1.6 There should be corresponding technical data for turbine operation. See Appendix A for the list of technical files and data.

4.2 Normal operation and requirements

4.2.1 Basic requirements for normal operation

a) Bucket-type turbines should be operated within the range allowed by the design.

b) During the operation of the turbine, its protection, signal and automatic devices should be normally turned on. The setting values of each protection, signal and automatic device shall be in accordance with regulations Set procedures.

4.2.2 No-load operation

a) The bucket-type turbine is not suitable to run for a long time at low speed during the process from starting to no-load. The governor should be put into operation in accordance with the prescribed procedure Insert the corresponding nozzle and adjust its opening to make the unit reach and stabilize at the rated speed along the starting curve.

b) For single-nozzle-started water turbines, when the no-load operation time is long after starting, the vibration, swing and water guide shaft of the turbine should be strengthened.

Support temperature monitoring.

4.2.3 Load operation

a) The symmetrical nozzle working mode should be adopted when the bucket turbine is running under load.

b) When the bucket turbine is running under load, the output power should not stay at the nozzle switching point set by the governor program. Occurs during operation when the nozzle switches back and forth, the set power should be adjusted in time.

c) To meet the power grid dispatching requirements, the bucket turbine should be operated in a high efficiency area as far as possible according to the operating characteristic curve.

4.3 Run operation

4.3.1 Start and stop operations

a) Automatic start and stop should be adopted under normal conditions. The first start-up after the unit is newly put into production and overhauled should be started manually on site.

b) Starting conditions

1) The inlet ball valve and downstream tail water gate are fully open.

2) The entrance door of the casing is closed.

3) The inlet ball valve and control system are working normally.

4) The speed control system and oil pressure device are normal.

5) The oil level of each bearing is normal and the oil quality is qualified.

6) The turbine protection and automatic devices are put into normal operation.

7) The unit has the starting conditions.

c) Auto boot

1) Check that the unit is in standby state and has the conditions for automatic startup.

2) The monitoring system executes the boot order.

3) Monitor that the automatic startup process is correct.

4) Check the unit status and the parameters are normal after the given start-up target is completed.

d) Automatic shutdown

1) The unit load meets the shutdown conditions, and the monitoring system executes the shutdown order.

2) The shutdown process of the monitoring unit is executed normally, and the braking system is normally activated when the corresponding speed is reached.

3) After the shutdown is completed, check that all parts of the unit are restored to standby status.

e) Manual boot

1) Check that the unit is in standby state and has the conditions for manual startup.

2) Put in the cooling water of the unit and check that the flow and water pressure of each part are normal.

3) Manually open the main nozzle and the corresponding nozzle to make the unit rotate.

4) When the speed of the standby group rises to 80%-90% of the rated speed, turn off the nozzle to the no-load opening.

5) Adjust and keep the unit speed at the rated value.

6) Put in the unit excitation and merge into the system as needed.

7) Check that the unit status and parameters are normal.

f) Manual shutdown

1) The load of the unit satisfies the shutdown conditions, de-loading and de-excitation.

2) Manually turn the nozzle fully closed and turn on the deflector to monitor the decrease of the unit speed.

3) For units with brake nozzles, when the speed drops to the braking allowable value, manually open the brake nozzles and the speed drops to mechanical braking when the value is allowed, manually close the brake nozzle and put in mechanical brake.

4) For units without brake nozzles, when the speed drops to the allowable value of mechanical brake, manually put on mechanical brake.

5) After the unit is stopped, the mechanical brake is manually exited, and the valves of the brake system return to the normal standby state.

6) Exit the cooling water of the unit.

7) After the shutdown is completed, check that all parts of the unit are restored to standby status.

4.3.2 Operation of inlet ball valve

a) Under normal circumstances, it should be opened and closed remotely through the monitoring system; the first opening and closing of the water inlet ball valve after overhaul should be carried out manually in steps on site.

b) For power stations with high water head or silt-laden rivers, the opening and closing of the inlet ball valve should be linked with the start and stop of the unit.

c) Opening conditions of the inlet ball valve

1) The speed control system is normal, the nozzle is fully closed, and the deflector is turned on.

2) The drain valve of the water distribution loop is fully closed.

3) The inlet ball valve control system works normally.

4) The water inlet ball valve is in the closed position, and the repair seal and mechanical lock (if any) exit.

d) The water inlet ball valve needs to be closed under the following conditions

1) The unit speed reaches the setting value of over-speed protection action.

2) The speed control system is faulty, and the nozzle and deflector are out of control.

3) Inspection and repair of nozzles, deflectors and their control circuits.

4) The speed control system drains oil and loses pressure.

5) The water distribution loop is leaking or the drain valve is not closed tightly.

6) Other tasks need to open the cabinet to enter the door.

4.3.3 Governor operation

a) Under normal circumstances, the governor should operate in "remote" and "automatic" modes. When the governor is running in manual mode, the operator must on-site guard and surveillance.

b) When the governor is switched between automatic and manual, the governor with disturbance-free switching function can be directly switched.

For functional governors, please pay attention to adjusting the opening limit, the given opening and the actual opening before switching to avoid disturbance.

c) When operating multiple nozzles in manual mode to increase or decrease load, it is advisable to keep the symmetrical nozzle openings consistent.

d) According to the governor setting program, the main nozzle selection switch has the following modes

1) The main nozzle of each startup can be arbitrarily selected through the governor cabinet.

2) The main nozzle will automatically switch in sequence after the governor auto-manual switch.

3) The main nozzles automatically switch in sequence after the unit is switched on and off once.

e) Nozzle drainage operation

1) When the penstock (diversion tunnel) needs to be emptied for inspection, the nozzle can be opened for drainage. Nozzle drainage should avoid flood Period of heavy sedimentation.

2) Check that the unit is shut down, the nozzle is fully closed, and the deflector is turned on.

3) Manually open the corresponding nozzle to a certain degree of opening, and ensure that the deflector is still in the operating state.

4) Adjust the number and opening of nozzles according to the required drainage flow.

5) After draining is completed, close the corresponding nozzle.

4.3.4 Maintenance and isolation of turbine

a) The unit is disconnected and shut down, and the electrical part is isolated for maintenance.

b) Close the water inlet ball valve and put in the maintenance seal and servomotor mechanical lock.

c) Empty the water distribution loop and keep the drain valve fully open.

d) If necessary, close the tail water gate.

e) When the governor is on the spot, switch the nozzles and deflectors, and after completing the test data measurement, disconnect the AC and DC power supplies.

f) Close the oil supply main valve of the oil pressure device of the speed control system, and relieve the pressure if necessary.

g) Close the oil, water, and gas system valves related to turbine maintenance.

h) Disconnect the power supply of related protection and automatic devices of the turbine.

i) Set up maintenance warning signs, and set up obvious physical isolation measures such as fences.

4.3.5 Isolation recovery

a) Check that the oil level of the bearing oil tank meets the requirements and the oil color is normal.

b) Restore the relevant protection and automatic devices of the turbine to normal.

c) Restore the oil, water and gas systems related to the turbine to normal.

d) The oil pressure device of the speed control system is re-pressurized and normal operation is restored.

e) The servomotor is filled with oil, the governor electromechanical linkage test is qualified, and the emergency shutdown time is determined to meet the requirements.

f) Check that the nozzle of the turbine is fully closed, the deflector is put in, and there is no leftover in the casing, and the casing entrance door is closed.

g) Fully start the tail water gate and lock the spindle.

h) Fully close the water distribution loop drain valve.

i) Exit the water inlet ball valve to repair the seal and the mechanical lock of the servomotor, and open the water inlet ball valve.

j) After the electrical part of the unit is back for use, check whether the unit's starting conditions are met as required.

4.4 Operation monitoring

4.4.1 Monitoring requirements

a) The on-site regulations should clearly stipulate the operation monitoring items, specific scope and requirements of bucket-type turbines, and record information and parameters.

b) The monitoring personnel should adjust, report and deal with the equipment parameters and other abnormalities in time.

4.4.2 Monitoring items

a) The upstream water level and the pressure of the water distribution loop, and the unit flow rate.

b) The operating status of the speed control system, the opening of the nozzle and the deflector of the turbine.

c) The maximum temperature of the babbitt bearing of the hydraulic turbine guide bearing does not exceed 70°C, the maximum oil temperature does not exceed 55°C, and the minimum is not lower than 10°C;

The highest temperature of the tile body using elastic metal plastic tiles does not exceed 55°C, and the highest oil temperature does not exceed 50°C.

d) The vibration value of the water guide bearing cover should not exceed the relevant regulations of GB/T 8564, and the vibration (swing) of the main shaft at the water guide bearing should not exceed Exceeds the limit value 1 (A/B zone limit) in Appendix B of GB/T 32584-2016, and the spindle swing does not exceed the bearing cold 70% of the state gap.

e) Pressure and flow rate of oil, water and gas system equipment.

f) The working conditions of automation components and systems, protection devices, and the indicators of the turbine.

g) The amount of water leakage from the nozzle and the state of the brake system in the stopped state.

4.5 Inspection

4.5.1 Routine inspection requirements

a) Each shift should be inspected at the specified time.

b) The inspection should follow the prescribed route and have clear inspection content.

c) See Appendix B for the main items and requirements of the inspection.

4.5.2 The patrol inspection and monitoring should be strengthened in the following situations of bucket water turbine

a) The equipment will resume operation after being newly commissioned or overhauled.

b) Put into operation after handling the accident.

c) The defects of the turbine and its auxiliary equipment have not been eliminated.

d) The operating parameters exceed the specified values.

e) During the operation period immediately after the test work is completed.

f) When the nozzle is operating in asymmetrical mode.

4.6 Abnormal operation and accident handling

4.6.1 General requirements

a) When there is an abnormality in the operation of the turbine, the personnel on duty should accurately judge the abnormality based on the monitoring alarm signal and the abnormal phenomenon of the equipment and take effective measures immediately to remove the threat to people and equipment and limit the expansion of the accident.

b) During the handling of the accident, without the consent of the person in charge on duty, it is not allowed to reset the accident signal or change the state of the on-site equipment, but it endangers personal safety Except for congruent emergencies.

c) The accident phenomenon and handling conditions should be recorded in time, the cause of the accident should be analyzed and corresponding preventive measures should be formulated..

d) In the following situations, the personnel on duty can directly stop the machine, close the water inlet ball valve, and close the butterfly valve/gate at the front of the penstock if necessary door.

1) The water inlet ball valve does not automatically close when the turbine speed rises to the over-speed protection setting value.

2) The governor fails, the nozzle cannot be closed out of control, and the deflector cannot be turned on out of control.

3) The oil pressure of the speed control system drops below the accident low oil pressure but the protection is not activated.

4) When the vibration and swing of the hydraulic turbine increase abnormally, exceed the allowable range and cannot be eliminated, which seriously threatens the safety of the equipment.

5) When the oil level of the water guide bearing drops sharply, there is a large amount of oil leakage, oil slinging, insufficient replenishment, and the tile temperature rises sharply.

6) When the casing access door is ruptured and the water leakage is serious, the ball valve pipeline valve or the ball valve shaft seal is damaged and a lot of water leaks, and there is a danger of flooding the workshop.

7) The water distribution ring pipe and the penstock are ruptured and leaking.

4.6.2 Abnormal operation

a) High temperature of water guide bearing

1) Closely monitor the temperature of water guide bearing bush and oil temperature.

2) Check the oil level and oil color of the water guide bearing oil groove, and conduct an oil quality test if necessary.

3) Check the pressure and flow of the cooling water of the water guide bearing, and adjust if necessary.

4) Check the vibration (shaft swing) of the turbine and adjust the load condition if necessary.

5) The temperature of the water guide bearing continues to rise and should be shut down for treatment.

b) Abnormal oil level of water guide bearing

1) Closely monitor the temperature of water guide bearing bush and oil temperature.

2) If the oil level in the oil tank is too high, check whether it is caused by water ingress. If water enters, stop the machine for processing. If the oil quality is qualified, adjust the oil level to normal range.

3) The oil level in the oil tank is too low. Check if there is leakage or overflow. If there is, try to eliminate and replenish oil, and stop processing if necessary.

c) The water guide bearing cooling water is interrupted or the water pressure drops

1) Closely monitor the temperature of water guide bearing bush and oil temperature.

2) Check whether the cooling water inlet and outlet valve positions are correct, and whether there is any leakage in the pipeline, and make corresponding adjustments and treatments.

3) Check the blockage of the cooling water filter and clean it if necessary.

4) Check the working condition of the technical water supply pump, and put in spare cooling water if necessary.

5) After the cooling water is interrupted, the continuous operation time of the turbine should not exceed the stipulation. If the interruption cannot be restored for a while, it should be shut down for treatment.

d) Turbine vibration (shaft swing) exceeds the specified value

1) Adjust the operating conditions of the unit and check whether the vibration (shaft swing) value drops.

2) Check the running condition of the water guide bearing, monitor the bearing temperature, and deal with the abnormality in time.

3) Check whether there is any serious abnormal noise in the water machine room and casing, and stop the machine for inspection if necessary.

4) If the value of vibration (shaft swing) continues to rise and the safe operation of the unit is endangered, stop the machine for processing.

e) Leakage of nozzle and deflector hydraulic control pipeline

1) According to the governor control mode, if the nozzle and the deflector can be independently controlled, the group of nozzles will exit work and be put into the deflector.

Isolate the leaking pipeline.

2) If the nozzle and deflector cannot be controlled independently, stop processing.

3) Treat the leaking point and clean up the oil leak.

f) Nozzle and deflec...