WO1992017687A1 - Systeme pour maintenir chaudes des turbines de grande puissance, essentiellement des turbines a vapeur - Google Patents

Systeme pour maintenir chaudes des turbines de grande puissance, essentiellement des turbines a vapeur Download PDF

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Publication number
WO1992017687A1
WO1992017687A1 PCT/ES1992/000029 ES9200029W WO9217687A1 WO 1992017687 A1 WO1992017687 A1 WO 1992017687A1 ES 9200029 W ES9200029 W ES 9200029W WO 9217687 A1 WO9217687 A1 WO 9217687A1
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WO
WIPO (PCT)
Prior art keywords
turbine
temperature
blankets
turbines
thermocouple
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/ES1992/000029
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English (en)
Spanish (es)
Inventor
Cruz Antonio Lara
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
SEVILLANA DE ELECTRICIDAD SA
Original Assignee
SEVILLANA DE ELECTRICIDAD SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by SEVILLANA DE ELECTRICIDAD SA filed Critical SEVILLANA DE ELECTRICIDAD SA
Publication of WO1992017687A1 publication Critical patent/WO1992017687A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
    • F01D25/00—Component parts, details, or accessories, not provided for in, or of interest apart from, other groups
    • F01D25/08—Cooling; Heating; Heat-insulation
    • F01D25/10—Heating, e.g. warming-up before starting
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
    • F01D17/00—Regulating or controlling by varying flow
    • F01D17/02—Arrangement of sensing elements
    • F01D17/08—Arrangement of sensing elements responsive to condition of working-fluid, e.g. pressure
    • F01D17/085—Arrangement of sensing elements responsive to condition of working-fluid, e.g. pressure to temperature
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
    • F01D19/00—Starting of machines or engines; Regulating, controlling, or safety means in connection therewith
    • F01D19/02—Starting of machines or engines; Regulating, controlling, or safety means in connection therewith dependent on temperature of component parts, e.g. of turbine-casing

Definitions

  • Hot maintenance system of high power turbines mainly steam turbines.
  • the present invention refers to a hot-maintenance system of high-power turbines, mainly steam turbines.
  • the working conditions of the Thermal power plants have varied substantially, since it is economic and energy diversification criteria that establish the planning of electricity production.
  • the boiler In the first phase that can be called the "boiler phase", the boiler is supplied with the necessary energy in order to raise its energy level to a certain value, based on heating a large mass with a surely improved performance, but That can be considered acceptable.
  • the second phase which can be called the “turbine phase”
  • the turbine In the second phase, which can be called the “turbine phase”, the turbine is heated, of relatively small mass, with a small amount of value (approximately 3% of the nominal value) coming from the boiler, taking into account the thermal gradient, especially the rotor, and the differential expansion between fixed and mobile parts.
  • the objective of the invention is to implement a hot maintenance system for the high and medium pressure bodies of the steam turbines, thus avoiding heating with cycle steam, by means of a system of electrical resistances suitably adapted. with the hot maintenance system you would get:
  • the operating rules of a turbine indicate that in order for it to be in the proper state for starting the rotor, it must reach a certain temperature level. Said temperature is the reference point in such a way that in lower temperatures the machine is considered cold, and before coupling to the network it is necessary to heat and homogenize temperatures by rolling with steam during the time and with the appropriate speed for it. on the other hand, if the temperature is higher than the mentioned reference point, the machine is considered hot, not requiring any waiting time; (The only requirement in this case is that the temperature of the main steam intake valves be greater than or equal to that of the steam saturation at the intake pressure).
  • the outer shell heats up (or cools) much faster than the rotor and inner shell.
  • the lower part (base) of the machine has greater heat losses than the upper part (cover).
  • the turbine hot maintenance system recommended here has been devised to meet these requirements, keeping the machine temperature at the appropriate level so that it is continuously in proper condition for quick start.
  • the system consists of three distinct parts: 1.- The heating blankets
  • Heating blankets consist of flexible electrical resistors housed inside a woven metal cord based on inconel wire. These heaters are stapled to a metal mesh that is part of the internal insulation blanket and rest on the turbine housing. When the electric power is switched on, the heating elements are heated and with the help of the insulating blankets the resulting temperature is maintained on the machine.
  • the power and distribution system consists mainly of a transformer, and a commutation module that can activate or deactivate a series of relays connected to the resistors of the electric energy blankets.
  • the characteristics of the system are determined based on the heat energy needed to heat the turbine and keep it warm at the setpoint temperature. This temperature is set taking into account the manufacturer's instructions regarding starts depending on the rotor temperature.
  • the heat flow needs are defined, in addition to the available data, as a result of a previous thermoelectric analysis performed on the turbine to study the response of the machine to situations called short rotor (higher average temperature in housing than in rotor) and for the greater cooling of the lower part of the housing relative to the upper one; effect called humping.
  • the data acquisition system (5AD) allows to know at any time the thermal and mechanical state of the turbine, regardless of its operational status.
  • the SAD consists of an automatic and computerized system, specific to this application, which offers flexibility and simplicity in its handling.
  • the data admission and control equipment consists mainly of a computer capable of filming the relevant program for both data acquisition and control along with its talus peripherals such as printer, plotter.
  • thermocouples that are distributed in the housing, in the main steam valves, of superheated steam and in the pipes.
  • the SAD based on the temperatures read, as well as the predetermined setpoints and the control laws used, decides in each control interval which zones should be under tension and which should not. From this information it gives activation orders to the relays corresponding to the resistors of the selected zones.
  • the SAD shows all the electrical signals coming from the sensors with the specified frequency, digitizes them and converts them into engineering units, automatically updates them and presents them by screen, printer and plotter. Its function consists also in supplying data to the system for the control of the heat power to be applied to the outer shell recognizing faults when there is an abnormal circumstance due to erroneous temperature signals producing alarms and even reaching the total disconnection of the resistors, when the number of thermocouples Wrong reaches a default value.
  • the SAD thus transcends what is strictly necessary to control the heating blankets, and allows to follow the evolution of the thermal and mechanical state of the turbine in a start-up, during normal operation or during cooling after the machine is fired.
  • the outer surface of the turbine is divided into zones. This distribution by zones is motivated by the different characteristics of 1 turbine surface (thickness, presence of pipes, etc ). Each zone can have one or several resistances due to the different heat contribution that each zone needs, although there is only one thermocouple for their government.
  • the control procedure is carried out cyclically. Each control cycle is the period of time between two consecutive samples and has two clearly differentiated parts. A part for data acquisition, checking and calculations by means of the control algorithms, during which the blankets are disconnected to avoid interference with the measurement signals and, a second part, available for heating, which ends with the next sampling moment.
  • the control system therefore, regulates the spatial and temporal distribution of the heat power applied to the outer shell with the basic objective of maintaining it at a temperature such that it ensures in the rotor sufficient temperature for a "hot" start. of the turbine.
  • Figure 1 shows a diagram of the installation of the hot maintenance system in high power turbines, object of the invention.
  • Figure 2 shows a detail of the installation of the heating blanket on the outer surface of the turbine, together with the heating, electrical elements and a thermocouple.
  • Figure 3 shows a block diagram representing the zone control function of the system.
  • Figure 4 shows a block diagram representing the "on-off" control strategy with PID master loop.
  • Figure 5 shows the response of the system to a simulation with the dynamic thermal model in a condition of heating from room temperature.
  • Figure 6 represents the response of the system to a simulation with the dynamic thermal model in cooling condition from firing conditions.
  • Figure 7 shows an elevation view of a device for installation, fastening and removal Thermocouple
  • Figure 8 shows the qualitative behavior of the strategy with master PID loop in heating condition from room temperature.
  • Figure 9 shows the qualitative behavior of the strategy with master PID loop in cooling condition from trip conditions.
  • Figure 10 represents a real situation of a cooling cycle of the turbine internal metal from a disconnection of the network produced by a trip and the response of the system to bring the temperature to the set point.
  • Figure 11 represents the variations of the temperature on the surface of the turbine and the response of the control system.
  • the system, object of the present invention consists of a turbine (1) on whose outer surface a series of resistors (2) are arranged to fulfill the heating function and a series of thermocouples ( 3) which serve to acquire data regarding the state of the machine.
  • the data acquisition and control equipment (4) consists of a computer with its peripheral equipment.
  • the system also consists of an electric power supply equipment comprising mainly a transform (5) and a switching module (6).
  • Figure 2 shows the arrangement of the heating blankets (7 and 8), the resistors (2) a thermocouple (3), and the corrugated mesh envelope (9) inside which houses a layer of heating blanket (7) and the electrical resistors (2).
  • the insulating assembly is composed, in a practical case, of three layers of removable blankets (the third layer has not been shown in the figure).
  • the thickness of each layer of blankets varies from the first to the third depending on the special function of each in terms of the insulation capacity required of each.
  • the blanket is installed directly on the outer shell of the turbine by means of anchors welded to it and represents the first insulation layer.
  • a type of fastening of the same has been designed, such that it is perfectly removable from the outside without the need to disassemble the mats, in addition to ensuring permanent contact between the end of the thermocouple and the surface to be measured.
  • Said fastening element consists of a hollow cylindrical protection tube (31) of cylindrical configuration (see figure 7), which has a conical configuration tip at one end and at the opposite end has a disc-like spreading with the diameter slightly. greater than the diameter of the tube.
  • This fastener (31) houses the thermocouple (3) inside it, protecting it from possible damage.
  • the signal that is collected from the thermocouple, by the data acquisition equipment (4), is conveniently processed and as a result admits a code to the zone selection module (6). With this code you order which resistors should activate this module. This will decode the received signal and activate the corresponding solid-state relays incorporated in the module. Relays that will allow the current from the power transformer (5) to pass through the general circuit breaker and circuit breakers also incorporated in the switching module (6). Finally, the selected resistors will heat the required areas. As for the relays, it should be mentioned that there is one for every two resistors (connected in series) and allows or closes the passage of electrical intensity towards the resistors. There are two clearly differentiated parts that concern the functional aspects of the data acquisition system (SAD), on the one hand, and the control system on the other. The software that supports both systems fully adapts to the operational and reliability needs that the application requires.
  • SAD data acquisition system
  • the SAD shows the electrical signals coming from the sensors with the frequency (sampling period) specified by the operator, digitizes them and converts the data to engineering units.
  • the data is stored in matrix form in the main memory of the computer; subsequently it is checked if the data is within the limits that define the range of the sensor.
  • the data displayed on the screen is automatically updated and recorded on the hard disk if applicable, according to the recording period specified by the operator.
  • the corresponding absolute time, measured with the computer's internal clock, is recorded next to the data.
  • the specific data corresponding to any previously defined group of variables can be presented in tabular form by printer and screen. In these peripherals, the evolution over time of any group of data can be presented graphically. The period of time covered by the representation depends on the recording period and the available RAM. Each variable can be represented as a percentage (of the sensor range) or in its own units.
  • the presentation on screen supports a zoom with automatic change of scales to appreciate details. Finally, on screen, it You can present the surface temperature map; the surface of the turbine is colored on a schematic figure of the turbine according to its thermal level.
  • the SAD supplies temperature data to the control system so that it manipulates the heat output dissipated in each zone. It is necessary, therefore, to have reliable data at all times for which the system must warn of any failure in the sensors and be protected immediately against them without waiting for repair.
  • Each zone carries at least two thermocouples, one of control and another of reserve called “gradient" in the case of failure in the thermocouples, these can give signals out of limits is easily detectable or, partially giving an erroneous signal, but within limits .
  • the designed protection system recognizes a fault when any of these circumstances occur: signal out of limit; signal change between two consecutive samples exceeding a preset limit; difference between control and gradient thermocouple exceeding a preset limit; difference between the signal of a thermocouple and the average of adjacent thermocouples exceeding a preset limit. In any of these circumstances the system gives an alarm and replaces the thermocouple signal that has failed with another according to a previously established sequence.
  • the system counts the thermocouples that fail and when their number exceeds a limit, which is specified by the system operator, it produces a total alarm and disconnection of the heating blankets.
  • b.- Heating blanket control procedure In order to distribute the heat output especially, the outer surface of the turbine is divided into zones. Although several heating blankets may correspond to the same zone, there is only one single temperature representative of each zone and a single control signal common to all blankets. In order to control the difference in cover-base temperatures, corresponding areas are defined as those having the same axial position are symmetrical with respect to the turbine axis.
  • a feedback control loop is established that has as a controlled variable the surface temperature measured by the thermocouple of the zone, and as a manipulated variable the heat output ceded by the blankets of said zone.
  • the set point can be local or remote, according to the strategy implemented, but it will always be the same for all areas, of the outer shell, and equal to the outer shell temperature necessary to reach the rotor temperature sufficient for starting hot, when the permanent regime is reached.
  • FIG 3 shows the zone control process, in which it is observed that the control computer based on the information received from the thermocouple and that established by the set point (TSET) on the one hand and the temperature of the zone corresponding (TEMP 1) on the other, sends the relevant orders, through the power supply equipment to the heating blankets (blanket), turning the resistors on and off according to the case, which results in a temperature adjustment in the zones surface of the housing (zone).
  • This new Temperature (TEMP 2) is detected by the corresponding thermocouple in the area which sends the respective signals to the computer.
  • the control cycle is the period of time elapsed between two consecutive samples.
  • the control algorithm calculates in each cycle, the fraction of the cycle time during which each blanket has to be connected; In this way, the average heat output for each zone in each cycle is regulated.
  • the control system regulates the spatial and temporal distribution of the heat power applied to the outer casing with the basic objective of maintaining it at a temperature such that it ensures in the rotor sufficient temperature for a "hot" start of the turbine.
  • the control strategy allows to stop the natural cooling process from any firing condition, or to heat the turbine from room temperature, to the technical state that allows a start hot.
  • Figures 5 and 6 show the qualitative behavior of this strategy obtained with a simple turbine simulation model.
  • the strategy is especially indicated to stop the cooling of the machine after a shot provided that the temperature to be maintained in the outer shells is previously known so that the rotor is at the SOAK temperature; or for cases where the desired temperature for the rotor does not change and the changes in ambient temperature are not excessive.
  • control system is able to find, by itself, the set point for the zonal control loops corresponding to the outer casing of the turbine.
  • power given by the blankets is modulated according to the differential expansion measured at each moment.
  • Figure 4 shows the block diagram corresponding to this strategy.
  • the master loop controls the temperature of the rotor by manipulating the set point of the zone loops.
  • the control algorithm contains proportional integral and derivative actions.
  • the control changes the set point of the zone loops while there is a difference between the desired temperature for the rotor and the temperature measured by a thermocouple that assumes (simulates) the temperature of the rotor.
  • the rotor When the permanent regime is reached, the rotor will have the desired temperature and the controller output will indicate the necessary surface temperature under those conditions.
  • the power modulator allows a high heating rate of the machine to be achieved while limiting differential expansion.
  • the system starts with the maximum power that has been specified to subsequently reduce it depending on the measured differential expansion.
  • the power applied is void before reaching the trip limit, which makes it impossible to reach it.
  • FIGS 8 and 9 show the qualitative behavior of the strategy with master PID loop.
  • the "on-off" strategy in the zonal bonds annuls the difference in cover-base temperatures and brings the surface temperature to the point of setpoint calculated with the master PID loop.
  • the PID master loop brings the rotor temperature to the desired temperature for a hot start.
  • the power modulator reduces the initial heating rate to limit differential expansion.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Control Of Turbines (AREA)

Abstract

Système permettant de maintenir chaudes des turbines de grande puissance, essentiellement des turbines à vapeur, basé sur sa capacité à prédire les éventuels comportements thermiques de la machine en fonction des variations de température pendant un refroidissement ou un réchauffement, ce système manipulant les températures du rotor et de la carcasse extérieure de la turbine pour obtenir et maintenir à l'intérieur de la turbine une température de consigne appropriée en vue d'effectuer un démarrage rapide sans avoir de besoin de préchauffage. Le système se compose d'un ensemble de couvertures chauffantes pourvues de résistances électriques et placées sur la surface extérieure de la turbine, un système d'acquisition de données et de commande automatique et informatisée ainsi qu'un système d'alimentation et de distribution de l'énergie électrique.
PCT/ES1992/000029 1991-03-26 1992-03-25 Systeme pour maintenir chaudes des turbines de grande puissance, essentiellement des turbines a vapeur Ceased WO1992017687A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
ESP9100793 1991-03-26
ES9100793A ES2029430A6 (es) 1991-03-26 1991-03-26 Sistema de mantenimiento en caliente de turbinas de gran potencia, principalmente de turbinas de vapor.

Publications (1)

Publication Number Publication Date
WO1992017687A1 true WO1992017687A1 (fr) 1992-10-15

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PCT/ES1992/000029 Ceased WO1992017687A1 (fr) 1991-03-26 1992-03-25 Systeme pour maintenir chaudes des turbines de grande puissance, essentiellement des turbines a vapeur

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EP (1) EP0537307A1 (fr)
ES (1) ES2029430A6 (fr)
WO (1) WO1992017687A1 (fr)

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NO306271B1 (no) * 1997-06-05 1999-10-11 Dynatrend As FremgangsmÕte i forbindelse med start av kraftturbin og fremgangsmÕte til pÕvisning av risiko for startskade pÕ kraftturbin
EP1674667A1 (fr) * 2004-12-21 2006-06-28 Siemens Aktiengesellschaft Procédé et dispositif pour le préchauffage d'une turbine à vapeur
EP2351912B1 (fr) * 2010-01-12 2019-05-15 Siemens Aktiengesellschaft Turbine avec système chauffant, centrale énergétique solaire et procédé d'exploitation associés
DE102011005122A1 (de) * 2011-03-04 2012-09-06 Siemens Aktiengesellschaft Dampfturbine insbesondere für solarthermische Kraftwerke
US8347598B2 (en) 2011-03-18 2013-01-08 General Electric Company Apparatus for starting up combined cycle power systems and method for assembling same
PL225446B1 (pl) 2013-04-30 2017-04-28 Gen Electric Zespół sterowania cieplnego dla turbiny, zespół wytwarzania energii elektrycznej zawierający turbinę oraz turbina zawierająca zespół sterowania cieplnego
DE102014220370A1 (de) 2014-10-08 2016-04-14 Siemens Aktiengesellschaft Warmhalten einer Dampfturbinenwelle mittels Induktion
DE102014220492A1 (de) 2014-10-09 2016-04-14 Siemens Aktiengesellschaft Vorrichtung zum lokalen Wärmeeintrag an einer Turbinenwelle
DE102014221566A1 (de) 2014-10-23 2016-04-28 Siemens Aktiengesellschaft Warmhalte-Konzept für schnelles Anfahren der Dampfturbine in GuD-Kraftwerken mithilfe eines Wärmespeichers
DE102014221563A1 (de) 2014-10-23 2016-04-28 Siemens Aktiengesellschaft Verfahren zur Verkürzung des Anfahrvorgangs einer Dampfturbine
DE102014221676A1 (de) 2014-10-24 2016-04-28 Siemens Aktiengesellschaft Warmhalte-Konzept für schnelles Anfahren der Dampfturbine in GuD-Kraftwerken: Einsatz von Inertgas
DE102015206320A1 (de) 2015-04-09 2016-11-10 Siemens Aktiengesellschaft Verfahren zur Verkürzung des Anfahrvorgangs einer Dampfturbine
CN105003305B (zh) * 2015-06-02 2017-05-31 苏州巨能发电配套设备有限公司 一种汽轮发电机整体机座及其装配工艺
US10337357B2 (en) 2017-01-31 2019-07-02 General Electric Company Steam turbine preheating system with a steam generator
US10174639B2 (en) 2017-01-31 2019-01-08 General Electric Company Steam turbine preheating system
US11603773B2 (en) 2020-04-28 2023-03-14 General Electric Company Turbomachinery heat transfer system
US12421905B2 (en) 2023-04-20 2025-09-23 Rolls-Royce North American Technologies, Inc. Thermal energy system to minimize or eliminate rotor bow
US12234741B2 (en) * 2023-04-20 2025-02-25 Rolls-Royce North American Technologies, Inc. Thermal energy system to minimize or eliminate rotor bow
CN120845138B (zh) * 2025-08-20 2026-04-07 东莞深燃天然气热电有限公司 基于多参数协同优化的汽轮机冷态启动滑参数智能调控方法及系统

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GB301298A (en) * 1927-11-26 1929-05-03 Bbc Brown Boveri & Cie Improvements in and relating to steam or gas turbines
DE945027C (de) * 1941-12-30 1956-06-28 Aeg Einrichtung zur Sicherung von Dampfkraftanlagen, insbesondere Dampfturbinen
GB877127A (en) * 1959-04-15 1961-09-13 Napier & Son Ltd Gas turbines
US4584836A (en) * 1985-01-29 1986-04-29 Westinghouse Electric Corp. Steam turbine restart temperature maintenance system and method

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB301298A (en) * 1927-11-26 1929-05-03 Bbc Brown Boveri & Cie Improvements in and relating to steam or gas turbines
DE945027C (de) * 1941-12-30 1956-06-28 Aeg Einrichtung zur Sicherung von Dampfkraftanlagen, insbesondere Dampfturbinen
GB877127A (en) * 1959-04-15 1961-09-13 Napier & Son Ltd Gas turbines
US4584836A (en) * 1985-01-29 1986-04-29 Westinghouse Electric Corp. Steam turbine restart temperature maintenance system and method

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Publication number Publication date
ES2029430A6 (es) 1992-08-01
EP0537307A1 (fr) 1993-04-21

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