With a poor governing system, these smaller, less abrupt, load changes can still result in an overspeed situation. Oct 22, 2008 steam turbines, second edition covers. Following figures show steam process in steam turbine. Jan 01, 2017 steam turbine control valve, governing and lube oil system subodh kumar tikadar general industrial steam turbine prefers a steam source of 42 kgcm2 600 psi at 482 oc 900 o f. Steam turbine governing steam turbine governing is the procedure of controlling the flow rate of steam into a steam turbine so as to maintain its speed of rotation as constant. The speed governing system consists of a proportional regulator, a speed relay, and a servomotor controlling the gate opening. Throttle control is suited for turbines dedicated for base load operation, oper. In a control context, a steam turbine can be regarded as a system with the valve lift hv as control input and the outgoing power p as the system output. Ed nelson is a tu rbo machinery consultant based in dickinson, texas. The output power of the turbine at steady flow condition is. The turbine electro hydraulic governor ehg control system controls steam flow to the turbine thorough a series of servodriven electrohydraulic valves. The performance of the steam turbine is governed by the losses occurred in it. A steam turbine is a mechanical device that extracts thermal energy from pressurized steam, and converts it into rotary motion. With an appendix on gas turbines and the future of heat engines.
Chaplin encyclopedia of life support systems eolss there is a loss in stage efficiency at the rate of about 1% for each 1% moisture content. In throttle governing the pressure of steam is reduced at the turbine entry thereby decreasing. Because the turbine generates rotary motion, it is particularly suited to driving electrical generators about 90% of all electricity generation in the united states 1996 is by use of steam turbines 1 wiser. Governing of steam turbine is the procedure of controlling the flow rate of steam to a steam turbine so as to maintain the speed of the turbine fairly constant irrespective of load on the turbine. In case of turbines with cooling water preheating and lowpressure lp bypass, prior to supplying steam the regeneration and dumping systems have to be. Steam has one great advantage over waterit expands in volume with tremendous velocity. The myr design combines the reliability and parts interchangeability of our popular yr turbine with the power and efficiency of multistage turbines. Nozzle governing of steam turbine with inner architecture for example if the turbine consists of 10 nozzles for full power100 %. Steam turbine governing and its mechanism ece tutorials. What is the function of a governor in a steam turbine. Excellent text on steam turbine design but now dated as it covers only smaller units. The first steam turbine rail locomotive was built in 1908 for the officine meccaniche miani silvestri grodona comi, milan, italy.
Then a steam turbine with a governing stage will be modelled. Power plant lecture notes chapter4 steam turbine chapter pdf. Steam turbine governor free download as powerpoint presentation. Instruction manual for single stage 350, 500, and 700 frame steam. The variation in load during the operation of a steam turbine can have a significant impact on its performance. Because of throttling of the steam at the inlet of the turbine there are important throttling losses.
Prior to supplying steam to the turbine, the steam supply pipelines have to be drained and heated up. The cbt also covers steam turbines and the governing system in detail and includes woodwardtype governor operation. Steam turbine governing is the procedure of controlling the flow rate of steam to a steam turbine so as to maintain its speed of rotation as constant. Steam turbine control valve, governing and lube oil system. If a full turn will not make the valve lift exactly 516 the remaining slight adjustment can be made by means of the.
Comparing combined gas tubrinesteam turbine and marine. Dec 23, 2017 the throttle governing is one of a method to sychronise the mass flow rate of steam through the turbine with the load requirement which can be learnt by this easy video lecture. Governor, steam chest and throttle valve it should be noted that as the pin in head 46 is off set, the spacer must be adjusted one full turn at a time. In noncondensing turbines or backpressure turbines, steam exhausts at a pressure greater than. Steam turbine control valve, governing and lube oil system subodh kumar tikadar general industrial steam turbine prefers a steam source of 42 kgcm2 600 psi at 482 oc 900 o f. Consider steam turbine drives for rotating equipment steam turbines are well suited as prime movers for driving boiler feedwater pumps, forced or induceddraft fans, blowers, air compressors, and other rotating equipment. If the load demand has reduced to 60 % then out of 10 nozzles, 4 nozzles can be closed to provide 60% load with out delay. It has almost completely replaced the reciprocating piston steam engine primarily because of its greater thermal efficiency and higher powertoweight ratio. The electronic governor may also improve plant production from driven equipment through enhanced steam management while providing realtime data on. Throttle regulation this governing is made by getting down the pressure of the steam, this is made.
The steam turbine is a turbine in which the potential energy of heated and compressed steam produced in a special device, a steam generator, or steam of natural origin for example, from geothermal springs is converted into kinetic energy when the steam expands in the turbine blade cascades and then into mechanical work on the rotating shaft. Nelson turbomachinery consultant dickinson, texas and perryc. He retired fro m amoco oil company, after more than 36 years in. A steam turbine locomotive engine is a steam locomotive driven by a steam turbine. Issn 2348 7968 it2flc based control model of steam turbine.
This provides a follow up of basic engineering cycles with applications to conventional power plants. Variable speed drives and intermediate gearing used for major process machinery and cogeneration drives with completely updated content arrangement, material composition, and basic physical laws governing design of steam turbines how to select optimum configurations, controls, and components options and. Modeling of the steam turbine and its governing a simplified construction of the steam turbine and its governing system is proposed in the fig. Issn 2348 7968 it2flc based control model of steam. The throttle governing is one of a method to sychronise the mass flow rate of steam through the turbine with the load requirement which can be learnt by this easy video lecture. Steam process in steam turbine steam entrance to turbine through governor valv e to control steam capacity and therefore to control turbine speed. Approval issue module 2347 the turbine governing system. It includes heat exchange and energy conversion equipment. Pdf power plant lecture notes chapter4 steam turbine.
Steam turbine performance 3 4 2 1 46 45 44 43 42 41 43 42 41 40 39 % % 1. P m h1h2where m is the mass flow of the steam through the turbine and h1 and h2 are specific enthalpy of the steam at inlet respective outlet of the turbine. It is used where system is subjected to variable loading. Automation and control of electric power generation and. Throttle governing in throttle governing the pressure of steam is reduced at the. The myr produces more power without additional steam, and can be installed in many areas where. Sliding pressure optimization method for steam turbine with. A steam turbine is a mechanical device that extracts thermal energy from pressurized steam and transforms it into mechanical work. Model the dynamics of speed governing system, steam turbine. Understanding and preventing steam turbine overspeeds by. Consider the steam turbine shown in the cycle above. The typical main turbine in nuclear power plants, in which steam expands from pressures about 6 mpa to pressures about 0. The modern digital turbine control system tcs is designed to control the main steam flow to the steam turbine in all operational conditions by means of the turbine throttle, governor, admission. An electronic governor can provide precise speed control with fewer wearing parts than an equivalent mechanical governor.
Friction losses, leakage losses, external losses, turbine governing and control. Consider steam turbine drives for rotating equipment. Steam turbine governing is the procedure of controlling the flow rate of steam to a steam turbine. Suppose, a steam turbine based power plant supplies power to an specific city. When the steam turbine oper ates in single valve mode, the regulation performance of steam turbine is much better, but the throttle loss is seri ous.
Pdf study on valve management of deh for steam turbine. The mitsubishi turbine ehg control system can be applied to a variety of turbine generator system designs. Unesco eolss sample chapters thermal power plants vol. Elec0047 power system dynamics, control and stability. In 1924 krupp built the steam turbine locomotive t18 001, operational in 1929, for deutsche reichsbahn. In order to understand the different control issues involved in governing steam turbines, some more details of possible steam turbine operation modes need to be elucidated. Hga excess air discharge flue gas temperature main steam condition reheat back pressure lhv. In principle they are far simpler than cylinder engines, steam being merely directed at a suitable angle on to specially shaped vanes attached to a revolving drum and shaft.
Steam turbine training governing system training course. Pdf portable document format pdf 68 care and maintenance. Figure 4 shows steam process in enthalpy against entropy diagram of curtis and single row rateau turbine. The conditions in the design situation are the same for the different turbine control situations. Steam turbines startups 1 principles of steam turbines startups. Model steam turbines steam turbines have come very much to the fore during recent years, especially for marine propulsion. Understanding and preventing steam turbine overspeeds by william e. This service generally calls for a backpressure noncondensing steam turbine. In a practical situation the load frequently varies from the designed or economic. The steam turbine and governor block implements a complete tandemcompound steam prime mover, including a speed governing system, a fourstage steam turbine, and a shaft with up to four masses. Turbine governing the steam flow through the control valve is proportional to the. For improved steam consumption, elliott engineers designed the multiyr myr steam turbine product line.
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