Voith Torque Converter Starting System for Gas Turbines

Transcription

1 Voith Torque Converter Starting System for Gas Turbines

2 Variable-Speed Drives We are the experts in hydrodynamic variable-speed drives at Voith Turbo. Voith Turbo, the specialist for hydrodynamic drive, coupling and braking systems for road, rail and industrial applications, as well as for ship propulsion systems, is a Group Division of Voith GmbH. Voith sets standards in the markets energy, oil & gas, paper, raw materials and transportation & automotive. Founded in 1867, Voith employs almost people, generates Euro 5.2 billion in sales, operates in about 50 countries around the world and is today one of the biggest family-owned companies in Europe.

3 Reliability & Availability: Choosing the right system is important Gas turbines are often started several times a day. Choosing the right starting system will affect the start-up reliability of the gas turbine. Voith supplies torque converters to all leading gas turbine manufacturers and their licensees, to start gas turbines ranging in power from 20 to 270 MW. The combination of an induction motor with a Voith torque converter is synonymous with trouble free start-ups, high reliability, and long service life. More than gas turbine starters worldwide is outstand ing evidence of our experience and know-how in this area. We believe no other starting system or method equals the reliability and availability of the Voith torque converter starting system. Our exceptionally high MTBF (mean time between failure) leads to a statistical reliability of %. We also know of no other starting system that matches the 35-year design life of the Voith torque converter; and this comes with a guaranteed availability of parts and service matching the life of our machines. The compact and rigid design offers trouble free operation while maintenance ex penses are at a minimum. T TC Starter System Generator Gas Turbine 2

4 Torque converter benefits, function and design The benefits Basic design hydrodynamic torque converter n Voith torque converters are designed and built to meet customer requirements. No other torque converter manufacturer offers this service. Guide vanes (adjustable) Pump wheel orsional vibration dampening and shock free power transmission; consequently, no stress applied to connected equipment thus delivering long service life. Turbine wheel n No-load starting condition on the starting motor by decoupling the motor from the load through the working oil shut-off valve feature. n Low maintenance expenses. he Voith torque converter decouples the starting motor from the gas turbine train during gas turbine operation without the need for a mechanical clutch through our exclusive working oil shut-off valve feature. n Smooth and stepless output speed and torque adjustment of the torque converter. The heart of Voith s hydrodynamic torque converter is its hydraulic circuit; consisting of a pump, turbine, and a guide wheel with adjustable guide vanes (see picture above right). This is combined in a common housing filled with hydraulic oil. The mechanical energy of the motor is converted into hydraulic energy through the pump wheel. In the turbine wheel the same hydraulic energy is converted back into mechanical energy and transmitted to the gas turbine / generator shaft. The adjustable vanes of the guide wheel regulate the mass flow in the circuit. At closed guide vanes (small mass flow) the power transmission is at its minimum. With the guide vanes comple tely open (large mass flow), the power transmission is at its max imum. Commonly, a constant speed driver such as an induction motor or a diesel engine drives the pump wheel (input shaft of the torque converter). Because of the change in mass flow (due to the adjustable guide vanes) the turbine wheels speed is variable and can be adjusted to match the various operating points of the gas turbine. At low speed, the turbine develops its highest torque. With increasing turbine speed, output torque decreases. 3

5 T T T P h = 0 h T T T P T T : Turbine torque T P : Pump torque h : Efficiency 1 : Turbine wheel 2 : Pump wheel 3 : Mass flow (oil) = max Typical gas turbine start-up curve 1 Typical gas turbine start-up curve Typical high speed setting Typical low speed setting Using a multi-position guide vane actuator, multiple hold points and acceleration speeds can easily be part of the control logic. 1 Breakaway 2 Unfired resistance 3 Purge point (air exchange) 4 Firing speed 5 Acceleration resistance to self sustained speed 6 Self-sustained speed = max = n opt = Torque 0 % Speed 6 Depending on the design of the turbine wheel the output torque at the break-away ( = 0) point is two to ten times that of the pump (input) torque. The guide vanes absorb the torque differential between the turbine (output) and the pump (input) and transfer it to the foundation. By placing the guide vanes upstream of the pump wheel, the torque requirement of the pump ( input) remains constant at a given guide vane setting, independent of the load on the turbine (output). That means an overload of the driver (motor or engine) is not possible through the hydraulic circuit. When the hydraulic fluid is removed from the torque converter circuit, the pump (input) is uncoupled from the turbine (output) and consequently, the starter motor or engine is disconnected from the gas turbine. 4

6 Typical starter system P&I diagram M 5 R Torque converter 2 Torque converter housing 3 Fill and drain valve 4 Control valve (Filling and draining) 5 Guide vane adjustment 6 Orifice plate 7 Working oil supply 8 Lube oil and cooling oil supply 9 Working oil return 10 Lube oil and cooling oil return 11 Lube oil tank of gas turbine T M M 11 Start Up Other Functions Through its characteristic of high torque at low output speed, the torque converter is the ideal gas turbine starter. With the abundant acceleration torque available, the gas turbine can be quickly accelerated to and above its self-sustained speed, an important requirement of the state-of-the-art, high temperature gas turbines. n Break-away of the gas turbine through the torque converter or the integral turning gear n Acceleration to purge speed n Acceleration to firing speed n Assisting the gas turbine to and above self sustained speed n Uncoupling the starting system from the gas turbine urning the gas turbine by means of the integral turning gear for slow-roll functions n Indexing the gas turbine for inspections n Fast spin-cooling of the gas turbine for rapid maintenance availability n Extended gas turbine water-wash cycles 5

7 Torque converter power chart Power chart Torque converter for gas turbine starting Torque converter in pump storage power plants Converter input power P P in MW Converter input speed n P in rpm Power versus input speed chart of exiting torque converters 6

8 Torque converter Model EL..Y the classic design Torque / speed characteristics = 100 % = 75 % = 50 % = 25 % = 0 % M P n P = constant : Guide vanes open T P : Input torque T T : Output torque n P : Input speed : Output speed T T / T P / n P The model EL..Y with its single stage turbine offers a torque multiplication factor of 4. Its balance of features and torque characteristics in combination with an integral turning gear makes it the ideal starter for a broad range of gas turbines. With the powerful hydrau lic guide vane system, controlled by solenoid valves or an electric actuator, the various operating points of the gas turbine are easily obtained. When combining the actuator with a 4-20 ma feed back system, the torque converter becomes a true variable speed drive with peak precision. The hydraulic fluid for the torque converter can be supplied by the gas turbine lube-oil system or through a complete packaged starter version including an oil reservoir system as available from VoithTurbo. Examples of other options for turning the gas turbine are: In stall ing a pony motor at the ODE of the start ing motor or installing a separate turning gear. Selection of EL..Y Starter Model EL 7,5 YFG 2.2 EL 10 YFG 6.5 EL 10,5 YG 10 Max. Input power (kw) Input speed (rpm)

9 Simplified longitudinal section of torque converter Type EL 10 YFG Input shaft 2 Pump wheel 3 Turbine wheel 4 Output shaft 5 Adjustable guide vanes 6 Adjusting mechanism 7 Filling and draining valve 8 Working oil supply 9 Working oil return 10 Lube oil return 11 Axial bearing 12 Radial bearing 13 Hydraulic cylinder 14 Guide vane actuator Type EL 10 YFG 6.5 Type EL 7,5 YFG 2.2 Type EL 10,5 YG 10 Ø100 Ø Ø80 Ø Ø119 Ø Dimensions in mm 8

10 Torque converter Model EL..Z the mighty one We call it the mighty one because, with its double stage turbine, it offers a torque multiplication factor of 10! It is used in applications with high break-away torque. For various operation points of the gas turbine, the guide vane adjustment is equipp ed, in this case, with an elec - tric actuator. The hydraulic fluid for the torque converter can be supplied by the gas turbine lube-oil-system or through a complete pack aged starter version including an oil reservoir system as available from Voith Turbo. By activating a simple solenoid valve the torque converter operating fluid is emptied from the torque con verter circuit and thus, uncouples the starting system from the gas turbine. Turning can be done using an integral or separate turning gear or a pony motor. Torque / speed characteristics = 100 % = 75 % = 50 % = 25 % = 0 % T P n P = constant : Guide vanes open T P : Input torque T T : Output torque n P : Input speed : Output speed T T / T P / n P 9

11 Selection of EL..Z Starter Model EL 10 ZFG Type EL 10 ZFG 1092 Max. Input power (kw) Input speed (rpm) Ø Ø Dimensions in mm Simplified longitudinal section of torque converter Type EL 10 ZFG 1 Input shaft 2 Pump wheel 3 Turbine wheel 4 Output shaft 5 Adjustable guide vanes 6 Adjusting mechanism 7 Filling and draining valve 8 Working oil supply 9 Working oil return 10 Lube and cooling oil return

12 Torque converter Model EL.. where power meets speed Torque / speed characteristics T T / T P T T = 100 % = 75 % = 50 % = 25 % = 0 % / n P T P T P : Guide vanes open T P : Input torque T T : Output torque n P : Input speed : Output speed With its single stage turbine and its torque multiplication factor of approximately 2, the EL.. model offers over-synchronous output speed. With the powerful hydraulic guide vane system, controlled by solenoid valves or an electric actu ator, the various operating points of the gas turbine are easily obtained. The robust, modular housing is designed for various torque con verter sizes as well as other torque converter types. The hydraulic fluid for the torque con verter can be supplied by the gas turbine lube-oil system or through a complete packaged starter version including an oil reservoir system as available from Voith Turbo. Turning can be done using an integral or separate turning gear or a pony motor. Selection of EL.. Starter Model EL 9 G 6.0 Max. Input power (kw) Input speed (rpm) Turning speed (rpm) Breakaway torque (Nm) 11

13 Simplified longitudinal section of torque converter Type EL 9 G Input shaft 2 Pump wheel 3 Turbine wheel 4 Output shaft 5 Adjustable guide vanes 6 Adjusting mechanism 7 Hydraulic cylinder for guide vane adjusting 8 Guide vane actuator 9 Housing 10 Fill and drain valve 11 Operating oil supply 12 Operating oil return Type EL 9 G 6.0 Type EL 10 GTM EL 9 GTM EL 10 GTM Ø100 Ø Ø119 Ø Dimensions in mm 12

14 Torque converter Model EL..YGTM with integral continuous turning gear Like many of Voiths torque converters, this powerful unit is equipped with an integrated turning gear connected to the output shaft with an over-running clutch. Among the advantages of this design are space savings and reduced cost through the elimination of an additional coupling and subsequently, reduced assem bly and alignment work. The turn ing gear is designed for long-life with emphasis on high break-away torque and long periods of lowspeed turning over the design life of 35 years. With this modular design, a large number of system combinations are available (different turning gear and torque converter sizes) per mitting a high degree of customization. A large number of this model torque converter are in oper ation world wide with integrated turn ing gears from 3600 ft-lb (5000 Nm) to ft-lb ( Nm). The turning gears are available with either AC or DC drive motors. In add ition, an electro-pneumatic turning device is available for con nection to the turning gear drive motor acces sory shaft for ultra-slow indexing of the gas turbine. The same turning gears are also avail able as stand alone units. Simplified longitudinal section of torque converter with integral turning gear Type EL 9 YGTM Input shaft 2 Output shaft 3 Pump wheel 4 Turbine wheel 5 Adjustable guide vanes 6 Housing 7 Filling and draining valve 8 Control valve for filling and draining 9 Working oil supply 10 Working oil return 11 Overrunning clutch 12 Worm gear 13 Electric motor 14 Bevel gear 13

15 Selection of EL..YGTM Type EL 9 YGTM Starter Model EL 9 YGTM EL 10,5 YGTM Max. Input power (kw) Input speed (rpm) Ø100 Ø Turning speed (rpm) Breakaway torque (Nm) Dimensions in mm

16 Torque converter EL..ZGTM with integral hydraulic turning device Simplified longitudinal section of torque converter with integral turning device Type EL 7,5 ZGTM 1 Input shaft 2 Output shaft 3 Pump wheel 4 Turbine wheel 5 Adjustable guide vanes 6 Housing 7 Filling and draining valve 8 Control valve for filling and draining 9 Working oil supply 10 Working oil return 11 Overrunning clutch 12 Return stroke piston / cylinder 13 Working stroke piston / cylinder This Voith torque converter with integrated hydraulic turning device is a well-proven design with hundreds of installations worldwide. Hydraulic cylinders produce the output torque, which is transmitted to the output shaft via an overrunning clutch. With each forward piston stroke, the gas turbine is turned 45 degrees. With its double stage turbine the torque converter offers a torque multiplication factor of 10. For the various operating points of the gas turbine, the guide vane adjustment system is equipped, in this case, with an electric actuator with various limit and position switches. 15

17 Selection of EL..ZGTM Type EL 7,5 ZGTM Starter Model EL 7,5 ZGTM EL 10 ZGTM-46 Max. Input power (kw) Input speed (rpm) Turning speed (rpm) 45 intermittent 45 intermittent Breakaway Torque (Nm) Ø80 Ø Dimensions in mm 16

18 Torque converter Type E.. with fixed guide vanes the compact one For gas turbines with a power of up to 45 MW, torque converters with fixed guide vanes are available and in operation in a large international fleet. The design is purposely built for high reliability and has a proven avail ability, superior to other types of starters. The output speed of this unit is controllable using a pressure reduction valve. Optionally, a hydraulic turning device can be integrated into this torque converter. Economical savings are achieved through the com pact and simple design. With its integral gear step, this torque converter can be easily matched to any gas turbine speed requirements. For starters, where a diesel engine is used instead of electric starting motor, the torque converter is ideally suited to the diesel motor characteristic and offers a no-load engine start. T T P T T / n P n P = constant Selection of E.. Starter Model E 5 WAT E 6 WAT E 6 YAT E 7 WAT E 7 W E 7 Y E 8 W Max. Input power (kw) 280 / / Input speed (rpm) / / Turning speed (rpm) Breakaway torque (Nm) 45 intermittent 45 intermittent 45 intermittent 45 intermittent T P : Input torque T T : Output torque 17

19 P&I diagram of Type E 7 WAT n P 3 R T 6 5 n a 1 Torque converter 2 Oil pump 3 Relief valve 4 Helical gear stage 5 Hydrostatic turning device 6 Overrunning clutch Simplified longitudinal section of torque converter Type E 7 WAT 1 Input shaft with connecting coupling 2 Pump wheel 3 Turbine wheel 4 Fixed guide vanes 5 Gear stage 6 Output shaft 7 Hydrostatic turning device 8 Working oil supply 9 Working oil return Type E 6 WAT 1092 Type E 7 W without turning device Ø447.7 Ø Ø447.7 Ø Ø620 Ø82 Ø127 Ø Dimensions in mm 18

20 Packaged Starter a complete-system solution Schematic diagram for oil circuit of El 9 G 6.0 Package 1 Torque converter 2 Torque converter housing 3 Starting motor 4 Control valve for guide vane position 5 Guide vane actuator 6 Transducer 7 Filter for control oil 8 Filling and draining valve 9 Thermocouples 10 Cooling oil 11 Indicator for guide vane position 12 Working oil pump 13 Pressure gauge lube oil pressure Voith engineers configure gas turbine starting packages specifically for your gas turbines. The table shows examples of starters in worldwide operation. The Voith engineers are eager to design and offer a system for your requirements. Gas Turbine Starters GT Starter Model EL 6,8 YFG EL 6,8 YFG EL 7,5 ZGTM EL 7,5 YGTM EL 7,5 YGTM EL 7,5 YGTM EL 10 YGTM EL 9 G 6.0 EL 9 G 6.0 EL 9 GTM Cranking (HP) Power (kw) Speed (rpm) Turning speed (rpm) 45 intermittent Breakaway Torque Nm ft-lbs Nm ft-lbs Nm ft-lbs Nm ft-lbs Nm ft-lbs Nm ft-lbs 19

21 Torque converter, motor, and all re- 13 quired accessory equipment are factory mounted on a common base. For more demanding requirements 2 such as retro-fitting to older gas turbines, the design can include an integral oil tank for a self contained, pack aged starter. An optionally available, onboard PLC system controls the various phases of the starting sequence. With this all- inclusive solu- 8 tion, site assembly, alignment, and commissioning time is greatly reduc ed. The components of the packaged starting system are select ed to compli ment each other, achiev ing an economical and space consc ious design. Due to the torque con verter character istic, the driver can be designed as a true starting motor. This means the driver (motor) can be used above its continuous rating during the short start-up of the gas turbine. This results in a smaller, space saving, and economical motor. Type EL 9 G 6.0 EL 10 GTM EL 10,5 YGTM Nm ft-lbs Nm ft-lbs Dimensions in mm 20

22 Voith Turbo GmbH & Co. KG Variable-Speed Drives Voithstr Crailsheim, Germany Tel Fax [email protected] Voith Turbo Inc. 25 Winship Road York, PA 17402, USA Tel Fax [email protected] cr228en, S&F-aik / SVG, , Dimensions and illustrations without obligation. Subject to modifications.