GB/T 21718-2021Fundamental technical requirements for small hydraulic turbines (English PDF)

5.2 Performance Guarantee

5.2.6 Regulation guarantee

When the unit rejects full load or partial load in any working condition, the pressure increase in the volute, the pressure decrease in the draft tube, and the speed increase rate should be Comply with the regulation guarantee calculation.

5.2.7 Guide vane (nozzle) leakage guarantee

5.2.7.1 Under the rated water head, the water leakage of the new conical guide vane of the counterattack turbine should not be greater than 0.4% of the rated flow of the turbine when it is fully closed;

The water leakage of the new non-tapered guide vane should not be greater than 0.3% of the rated flow of the turbine when it is fully closed.

5.2.7.2 The new nozzles of bucket, oblique and double-click turbines should not leak water when they are fully closed.

5.2.8 Guarantee of maximum axial water thrust

The maximum axial water thrust of the turbine should be guaranteed under various operating conditions.

5.2.9 Guarantee of Maximum Runaway Speed

The maximum runaway speed should be guaranteed under the following conditions.

a) Francis turbines and fixed-propeller turbines should take the runaway speed generated under the maximum water head and the maximum allowable guide vane opening.

b) The impulse turbine should take the runaway speed generated under the maximum water head and maximum nozzle opening.

c) The rotor blade type turbine should be the maximum runaway speed generated within the operating head range under the condition of the combination of the guide vane and the runner blade.

In the case of destruction of the association relationship, the maximum runaway speed generated within the operating head range can be taken.

5.2.10 Reliability guarantee

5.2.10.1 Under clean water conditions, the service life before decommissioning, a turbine with a unit power of 500kW~1000kW should not be less than 25 years;

The turbines of 1000kW (inclusive) ~ 5000kW should not be less than 30 years; the turbines of the unit power of 5000kW (inclusive) ~ 10000kW should not be Should be less than 35 years.

5.2.10.2 Under clean water conditions, the interval between overhauls (referring to the runner and guide vane lifted out for repair), the turbine with a unit power of less than 1000 kW does not It should be less than 3 years; hydraulic turbines with a unit power of 1000kW~5000kW should not be less than 4 years; turbines above 5000kW should not be less than 5 years.

5.3 Main component structure and material requirements

5.3.1 General requirements

5.3.1.1 The structural design of the hydraulic turbine shall meet the layout requirements of the powerhouse of the hydropower station, and comprehensive consideration shall be given to the connection between generators, governors, inlet valves and other equipment.

The mutual relationship between them is convenient for inspection and maintenance.

5.3.1.2 The structure of the turbine should be easy to assemble, disassemble and repair, and the vulnerable parts should be easy to check and replace.

5.3.1.3 The structural design of the hydraulic turbine shall ensure that the main components such as the generator rotor, stator, turbine top cover, and main shaft are not disassembled. Replace the following parts.

a) Hydraulic turbine guide bush and cooler, and main shaft working seal;

b) Impact turbine servomotor seals and piston rings, water guiding mechanism transmission parts and protection components, and runners with a diameter of 2.5m or more Paddle seals for rotary blade turbines;

c) The nozzle, deflector and runner of the impulse turbine.

5.3.1.4 The main structural components of the turbine shall have sufficient strength and rigidity under all working conditions.

5.3.1.5 The standard parts and components of the hydraulic turbine shall be universal. The main matching parts should be interchangeable.

5.3.1.6 The steel castings of the flow-through components of the turbine should meet the requirements of GB/T 10969, and the main shaft forgings should meet the requirements of JB/T 1270.

The testing of steel castings should meet the requirements of GB/T 7233 (all parts), and the testing of steel forgings should meet the requirements of GB/T 6402.

5.3.1.7 The important welds of the main parts of the turbine shall be inspected by 100% ultrasonic non-destructive inspection. For components with high stress or doubtful The parts can be checked by TOFD flaw detection according to DL/T 330 or NB/T 47013.10.

5.3.1.8 Fasteners or pipes and valves in contact with water or in wet locations shall be made of rust-resistant and corrosion-resistant materials or made of corresponding materials.

According to the appropriate protective measures, a protective coating layer should be provided on the surface of the turbine equipment.

5.3.1.9 The material of the turbine shall have good fatigue resistance, cavitation erosion resistance, abrasion resistance and corrosion resistance compatible with the water quality conditions of the hydropower station.

The runner and other parts prone to cavitation and wear of the turbine should be made of anti-cavitation and anti-wear materials in accordance with the provisions of GB/T 32745. Take necessary protective measures.

5.3.1.10 The counterattack turbine should be equipped with an emergency stop air supplement device, and the Francis and axial flow turbine should be equipped with a reliable anti-lifting machine and stop push device.

The counterattack turbine should adopt natural air supply from the draft tube or other vibration reduction measures to ensure the stable operation of the unit.

5.3.1.11 The top of the pressure pipe behind the inlet valve of the vertical-axis counterattack turbine should be equipped with automatic air supplement and exhaust devices.

The top of the volute should be equipped with an exhaust device.

5.3.1.12 Reliable drainage facilities should be provided on the top cover of the counterattack turbine, and backup facilities should be provided; the water level control and signal devices used for drainage should be reliable.

5.3.1.13 The guide vane shearing pin and the guide vane maximum opening limit device should be provided for the water guide mechanism of the counterattack turbine. The shear pin protection device is missing When effective, it can automatically alarm.

5.3.1.14 The runner chamber, volute, inlet pipe and draft tube of the counterattack turbine shall be provided with observation holes or manholes. The diameter of the manholes should not be smaller than 600mm, the lower side of the manhole should be equipped with a water test valve. The manhole of the water inlet pipe of the shaft extension tubular turbine should be set near the bulb body. top.

5.3.1.15 The hydraulic turbine shall have necessary anti-runaway facilities, and the duration of the allowable runaway speed of the turbine shall be no less than 5 minutes. At the biggest runaway Under speed conditions, the turbine components should not be harmfully deformed.

5.3.1.16 The turbine runner shall be designed according to fatigue strength.

5.3.1.17 The motor should have an anti-overload protection device.

5.3.2 Francis and axial flow turbines

5.3.2.1 The runner and the runner chamber

5.3.2.1.1 The surface profile of the runner should be geometrically similar to the model. The surface profile, wave degree and roughness of the flow surface should conform to GB/T 10969 Provisions.

5.3.2.1.2 The runner should be made of materials with good cavitation resistance, abrasion resistance and good welding performance. Made of stainless steel.

5.3.2.1.3 The runner should be inspected by non-destructive flaw detection in the manufacturer.

5.3.2.1.4 The pivot seals of the runner blades of axial-flow paddle turbines should be made of multiple layers of oil- and pressure-resistant materials. The runner and runner blades should adopt special Use tools for lifting, it is not advisable to open lifting holes on the blades.

5.3.2.2 Spindle

The main shaft should meet the torque requirement of the generator to transmit the maximum power, and the non-destructive inspection should be done in the manufacturer.

5.3.2.3 Spindle seal

The main shaft working seal should be reliable, wear-resistant, simple in structure, and easy to observe and repair. It is advisable to install an overhaul seal under the working seal of the spindle to After stopping, the working seal can be adjusted or replaced without closing the upstream and downstream gates.

5.3.2.4 Bearing

5.3.2.4.1 The bearing structure should be safe, reliable and easy to overhaul. During the entire process of the unit coasting from the maximum runaway speed to shutdown, it should be Take it safely.

5.3.2.4.2 The thin oil lubricated bearing should adopt the self-circulation method, and it should be ensured that no oil leaks and no oil is thrown during operation. For high-speed units, bearing oil The groove should be sealed against oil throwing and oil mist.

5.3.2.5 Seat ring

When the volute is emptied, the seat ring should be able to bear the entire weight of the structure placed on it and the rotating part of the unit, and can safely bear the weight of the volute.

The load generated by the maximum water pressure in the shell. The flow surface of the seat ring should meet the requirements of GB/T 10969.

5.3.2.6 Volute

5.3.2.6.1 The strength design of the metal spiral case does not consider the joint force of concrete, and should be able to withstand the maximum load that may occur.

5.3.2.6.2 The flow surface of the metal volute shall be smooth and non-destructive inspection shall be carried out in accordance with the regulations. The metal volute made by welding, outside the weld The concept should meet the requirements specified in GB/T 8564. The quality of the welding seam is in accordance with the provisions of GB/T 11345, and the circumferential seam should reach the level of BII. The longitudinal seam, volute and seat The butt weld of the ring connection should meet the requirements of Class B I; or according to the provisions of NB/T 47013.10, the ring seam should reach Class II, and the longitudinal seam, volute and The butt weld of the seat ring connection shall meet the requirements of Class I.

5.3.2.6.3 Where the transportation conditions permit, the seat ring and the metal volute shall be welded or cast as a whole in the manufacturer. If the metal volute If the size does not meet the transportation conditions, it should be manufactured in sections, pre-installed in the factory, and transported in sections, and measures to prevent deformation should be provided.

5.3.2.7 Water guiding mechanism

5.3.2.7.1 The guide vanes should be made of materials with good cavitation erosion resistance. The profile, wave and roughness of the flow surface shall comply with GB/T 10969 Provisions.

5.3.2.7.2 Stainless steel anti-wear plates or other anti-wear materials should be installed on the flow surface of the top cover and bottom ring corresponding to the range of the guide vane movement. Protection.

5.3.2.7.3 For Francis turbines, stainless steel fixed leak-proof rings should be installed at the corresponding positions of the top cover and bottom ring and the runner's leak-proof ring.

5.3.2.7.4 All shaft sleeves in the water guiding mechanism shall be made of self-lubricating materials. The shaft sleeve hole of the bottom ring should be concentric with the shaft sleeve hole on the top cover.

5.3.2.7.5 The water guide mechanism should be pre-installed in the manufacturer, and the relationship between the control loop stroke and the guide vane opening should be tested. When the guide vane is fully closed, Elevation clearance and end face clearance should meet the requirements of GB/T 8564.

5.3.2.7.6 The guide vane limit device should be installed.

5.3.2.8 Draft tube

A portable maintenance platform that is easy to disassemble and assemble should be set in the draft tube.

5.3.3 Tubular turbine

5.3.3.1 Runner

The requirements for the runner of a tubular blade turbine shall meet the requirements of 5.3.2.1.

5.3.3.2 Runner chamber

5.3.3.2.1 The interior surface of the runner of a rotary-propeller unit should adopt a spherical structure or a hemispherical structure, and the runner chamber of a fixed-propeller unit can also adopt a cylindrical structure. structure.

5.3.3.2.2 A telescopic flange should be installed behind the runner chamber of the tubular turbine, and the telescopic length should not be less than 10mm.

5.3.3.3 Tube type seat

Pipe-type seat should be provided with pipelines and cable channels. Tubular turbines with a runner diameter of more than 2.5m should be provided with maintenance personnel passing through Shaft passage.

5.3.3.4 Bearing

5.3.3.4.1 Tubular turbines should be equipped with guide bearings and forward and reverse thrust bearings. When the load of the guide bearing is large, a high-pressure jacking device should be provided.

5.3.3.4.2 When the bearing lubrication system adopts the high-level oil tank circulating oil supply method, the oil tank capacity should be able to ensure that the bearing continues to be installed when the oil supply pump fails. Run for more than 5 minutes.

5.3.3.5 Water guiding mechanism

5.3.3.5.1 Both ends of the guide vane, the inner surface of the outer guide ring, and the outer surface of the inner guide ring shall all be spherical structures. The clearance after the guide vane overlaps should meet The provisions of GB/T 10969.

5.3.3.5.2 The guide vane connecting rod shall be of an adjustable length structure with spherical hinges at both ends. Guide vane bearings and connecting rod bearings should be self-lubricating The composite bearing bush does not need to add lubricating oil during operation.

5.3.3.6 Spindle and spindle seal

The requirements for the spindle and spindle seal should meet the requirements of 5.3.2.2 and 5.3.2.3.

5.3.3.7 Increasing gear

When a speed increaser is used in a tubular unit, the speed increase gearbox should meet the requirements of GB/T 19073.

5.3.4 Bucket and oblique impact turbines

5.3.4.1 The runner, nozzle and spray needle should be made of anti-wear materials. The runner can adopt integral casting or cast-welded structure, and the necessary heat treatment and Flaw inspection.

5.3.4.2 When the unit load rejection, the deflector should be able to automatically and quickly fold water to prevent the unit from running away.

5.3.4.3 Bucket turbines can be equipped with reverse brake nozzles as required.

5.3.4.4 Each nozzle should have a separate operating servomotor. Each spray needle should have a separate opening indication, and the deflector should have a separate opening and closing position Set indicator signal.

5.3.4.5 If the needle actuator is operated by an asynchronous motor, a reliable limit switch should be set. The motor should have an anti-overload protection device.

5.3.4.6 The discharge height and ventilation height should be able to meet the requirements for safe and stable operation of the turbine.

5.3.4.7 The enclosure should have good vibration resistance.

5.3.4.8 The size and shape of the casing shall ensure unblocked drainage, and shall have necessary air supplement, sound insulation or noise reduction measures.

5.3.4.9 A drain hole should be provided at the lowest point of the water inlet pipe, and a cleaning hole should be opened on the side near the nozzle guide frame.

5.3.4.10 A stable water grid should be provided at the tail water. Vibration and deviation under various operating conditions should not exceed the allowable range, water distribution pipes and nozzles Water pressure test should be carried out.

5.3.4.11 The main shaft and bearings shall meet the requirements of 5.3.2.2 and 5.3.2.4.

5.3.5 Double-click turbine

5.3.5.1 An air supply valve for adjusting the water level in the draft tube shall be provided on the frame.

5.3.5.2 If the control water guiding mechanism adopts manual or electric operation, a reliable limit switch shall be provided. Equipped with reliable hand and electric switching device, in The motor should be powered off during manual operation.

5.3.5.3 The discharge height should be sufficient for the safe and stable operation of the turbine and the efficiency will not be affected.

5.3.5.4 The main shaft and bearing shall meet the requirements of 5.3.2.2 and 5.3.2.4.

6.1 Turbine body

It can include the metal volute and extension of the hydraulic turbine, the seat ring (tubular seat), the runner, the main shaft, the bearing, the runner chamber, the water guiding mechanism, the pit lining, the tail Metal linings of water pipes, drainage devices, and other ancillary equipment foundation embedded parts and adjustment fixing parts, etc. Horizontal Francis turbine should also include Water elbow and flange, flywheel and flywheel cover and brake device. The impulse turbine shall include the water distribution pipe, the casing, the nozzle, the spray needle and the spray needle moving machine Structure, deflector, etc.

6.2 Automation components (devices) and instruments

6.2.1 Automation components (devices) and instruments include the pressure, vacuum, flow, and temperature that need to be monitored during operation of the turbine and its auxiliary equipment.

Pressure, vibration, swing meters and related panels, as well as oil, gas, and water pipelines are differential pressure signal meters, liquid level signal meters, and flow signals that meet automatic control.

Signal device, temperature signal device, stroke signal device, hydraulic and pneumatic components and transmitters, etc.

6.2.2 The automatic component configuration of the small water turbine is in accordance with A.1 in Appendix A, and the instrument configuration is in accordance with A.2.

6.2.3 The connecting cables between the components and equipment in the machine pit should be supplied to the machine pit terminal box.

6.3 Piping and its accessories

The oil pipes, air pipes, water pipes, water filters, connectors and brackets required between the individual equipment in the complete set of equipment, all oil, gas, and water pipelines It should be supplied to a place 1m outside the turbine pit.

6.4 Special tools required for installation and maintenance

Refer to Appendix B for the configuration of special tools.

6.5 Spare parts

See Appendix C for the spare parts of the turbine.