JP3613690B2 - Turbine control method and control apparatus - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a turbine control method and control apparatus including a heater that reheats exhaust gas from a high-pressure turbine and supplies it for driving a low-pressure turbine, and more particularly, a steam turbine that has a large daily load change width and a large necessity for rapid start-up. And a control method improved to balance the heat exchange between the pre-stage heater and the post-stage heater constituting the multi-stage reheat type heater and to protect the heater from thermal deformation, etc. The present invention relates to a control device.
[0002]
[Prior art]
As a method for controlling the heating steam of the steam turbine heater, for example, Japanese Patent Application Laid-Open No. 63-16409 discloses an inlet / outlet temperature difference of a moisture separation reheater equipped with first and second stage heaters and a low-pressure turbine inlet steam temperature. It is disclosed to detect the rate of change of the second and control the second stage heating steam. In this method, since the control is performed using the temperature obtained by adding the heating amounts of the first stage and the second stage, the individual heat exchange balance of each stage heater cannot be monitored.
[0003]
Japanese Patent Application Laid-Open No. 1-230908 discloses a method in which when the first stage heater fails, this is stopped, the pressure setting function of the second stage heater is switched, and the second stage heater is operated independently. It is disclosed. However, in this method, when an abnormality that does not reach the switching point occurs due to the failure detection of the first stage heater, the temperature difference between the inlet and outlet of the second stage heater becomes large, and the first stage heater is completely connected above the switching point. Therefore, it is considered that there is a problem that the heat exchange amount of the moisture separator / heater rapidly decreases.
[0004]
[Problems to be solved by the invention]
When main steam is used as heating steam in a steam turbine having a heater, if the high-pressure turbine outlet steam is at a low temperature, each stage heater constituting the heater uses the high-pressure turbine outlet steam flowing into the main steam and the main steam. The amount of heat exchange with the high-temperature heating steam is large, a temperature difference is caused by rapid heating at the entrance and exit of each stage heater, and thermal deformation of each stage heater body occurs. In order to prevent this, the heating steam system is provided with a flow rate adjustment mechanism, the main steam as the steam source is depressurized and supplied to the subsequent stage heater, and the temperature difference between the high-pressure turbine outlet steam and the heating steam is within the specified value. It is necessary to control it to be smaller.
[0005]
As this control method, the heating steam pressure is set by the turbine output and the heating steam flow rate for each turbine output is controlled, or the rate of change is limited for this pressure control setting. There is a method to mitigate the rate of change of the reheat steam temperature.
[0006]
This method is effective if the reheat method is a one-stage reheat method using main steam as a heating source, but in the case of a multi-stage reheat method installed in a large-capacity steam turbine, Since the amount of heating steam is controlled in a state in which the amount of heat exchange by the heater is unclear, it is difficult to obtain an optimum reheat steam temperature with a subsequent heater.
[0007]
In general, when a steam turbine has two or more stages of heaters, each stage heater is planned to specify the amount of heat to be handled, and the previous stage heater cannot be exchanged due to a failure or the like. In such a case, in the latter stage heater, a temperature mismatch between the steam to be heated and the heating steam or a difference in temperature at the heater inlet / outlet will occur.
[0008]
For example, in a two-stage reheating system, if the high-pressure turbine outlet steam at a temperature of 192 ° C. is heated to 222 ° C. by the first stage heater and 264 ° C. by the second stage heater in a steady state, in this case The inlet / outlet temperature difference of the first heater is 222 ° C.-192 ° C. = 30 ° C., and the inlet / outlet temperature difference of the second stage heater is 264 ° C.-222 ° C. = 42 ° C.
[0009]
If the first stage heater malfunctions and the temperature of the first stage heater outlet steam decreases, the heat balance of the second stage heater deteriorates as the temperature decreases. Consider the case where the first stage heater stops due to a failure. In the second stage heater, if heat exchange is performed by heating steam at 282 ° C., the temperature of the heating steam used for heating in the second stage heater and the temperature of the steam flowing into the second stage heater (= first The difference from the outlet temperature of the stage heater increases from 282 ° C.-222 ° C. = 60 ° C. at the steady state to 282 ° C.-192 ° C. = 90 ° C. at the time of failure stop. Will be invited.
[0010]
The present invention has been made in view of the above circumstances, and by reusing the state quantity of the outlet steam of the pre-stage heater as a control factor for the heated steam introduced into the post-stage heater, it is reheated to an optimum temperature. It is an object of the present invention to provide a turbine control method and a control apparatus that can supply steam from the outlet of the subsequent stage heater and can protect the subsequent stage heater when the preceding stage heater malfunctions or stops.
[0011]
[Means for Solving the Problems]
In the steam turbine of the reheat system of two or more stages, the present invention uses the extraction steam of the high-pressure turbine as the heating steam source of the first stage heater, and a part of the main steam as the heating steam source of the second stage heater. When a reheater is installed to reheat the high-pressure turbine outlet steam, the state quantity (flow rate, temperature) of the high-pressure turbine outlet steam is calculated from the turbine output or the high-pressure turbine outlet steam pressure. The outlet temperature of the first stage heater is calculated by calculating the amount of heat exchange with the quantity, the required flow rate of the second stage heating steam is determined, the heating steam control valve is controlled, and the output of the turbine is changed. It is the method of relieving the temperature change of the accompanying steam turbine reheater exit steam.
[0012]
That is, in order to achieve the above object, the first turbine control method of the present invention reheats the outlet steam (P ₀ ) of a high-pressure turbine driven by main steam supplied from a steam source through a steam control valve, In order to supply the reheated steam (T ₁ ′) for driving the low-pressure turbine, the high-pressure turbine extraction steam (P ₀ ) as the heating steam extracted from the high-pressure turbine is used as the incoming high-pressure turbine outlet steam (P ₀ ). The first stage heater that heats by exchanging heat by P ₁ ), and the steam (T ₁ ′) heated by the first stage heater as the heated steam introduced from the steam source through the heating steam control valve A method of controlling a reheater comprising a second stage heater that is heated by exchanging heat (T ₂ ′) with a part (P ₂ ) of main steam and is supplied to a low-pressure turbine, (1 ) pressure at the outlet steam of the high pressure turbine (P ) To calculate the temperature and flow rate of the steam from (2) to calculate the temperature and flow rate of the extraction steam (P ₁₎ from the extraction steam of the high pressure turbine (P _1), (3) a high pressure turbine outlet steam (P ₁ ) And the temperature and flow rate of the extraction steam (P ₁ ) of the high-pressure turbine, and the extraction steam of the high-pressure turbine introduced into the first stage heater and the outlet steam of the high-pressure turbine introduced into the first stage heater. The temperature (T ₁ ′) of the outlet steam of the first stage heater that is reheated and flows out by heat exchange with the steam (P ₁ ) is calculated, and (4) the temperature of the outlet steam of the first stage heater ( The flow rate of a part (P ₂ ) of the main steam introduced into the second stage heater from T ₁ ′) and the flow rate and the temperature calculated from the pressure of the main steam part (P ₂ ) is as follows: (5) The flow rate of a part of the main steam (P ₂ ) is calculated as the outlet steam of the first stage heater and The outlet steam of the first stage heater and the temperature (T ₂ ′) of the outlet steam of the second stage heater that flows out by exchanging heat with part of the main steam (P ₂ ) introduced into the second stage heater, Is calculated as a flow rate such that the temperature difference is equal to or less than the temperature difference defined by the deformation allowable amount of the second stage heater, and is controlled by the heating steam control valve so as to be this flow rate.
Here, P ₁ , T ₁ ′, etc. shown in parentheses are the same as the symbols described in the drawings.
[0013]
By the way, since saturated steam is used in the steam turbine, the steam temperature is uniquely determined by the steam pressure. The steam flow rate is proportional to the steam pressure if the flow path cross-sectional area is constant. Therefore, if the steam path is fixed, the steam flow rate is proportional to the steam pressure. Therefore, the steam temperature and the steam flow rate can be calculated from the steam pressure.
[0014]
By using the heating steam control method as described above, even when the heat exchange amount is reduced due to a failure of the first stage heater, control is automatically performed so as to narrow down the second stage heating steam flow rate. Further, it is possible to prevent excessive heating of the subsequent heater.
[0015]
Further, the second turbine control method of the present invention is similar to the control method of the first steam turbine reheater, in that the steam source, the steam control valve, the high pressure turbine, the first stage heater and the second A turbine control method comprising a heater composed of a stage heater and a low-pressure turbine, and supplying a second stage heating steam amount to be supplied to a second stage heater defined according to each turbine output For this purpose, (1) the high pressure turbine outlet pressure (P ₀ ) using a function for obtaining the steam pressure corresponding to the heating steam amount optimal for heat exchange in the second stage heater with respect to the high pressure turbine outlet steam pressure (P ₀ ). ₀ ) based on the second stage heating steam pressure (P2a) set value, and (2) heating steam that is optimal for heat exchange in the second stage heater with respect to the high-pressure turbine bleed steam pressure (P ₁ ) First-stage heating steam using a function to determine the steam pressure corresponding to the volume Set the second stage heating steam pressure (P2b) setpoint flow rate _{(P 1)} based on, (3) a second stage heating steam pressure (P2a) set value set from the high pressure turbine outlet steam pressure _{(P 0)} The second stage heating steam pressure (P2b) set value set from the first stage heating steam pressure (P ₁ ) is compared, and the lower one of the two setting values (P2a, P2b) is given priority. (2) The opening degree of the heating steam control valve is controlled by feedback control so that the second heating steam pressure becomes equal to the final setting value (P2c).
Here, P ₁ , T ₁ ′, etc. shown in parentheses are the same as the symbols shown in FIG.
[0016]
According to the control method for each turbine described above, in a steam turbine having a reheat system of two or more stages, the flow rate of the heating steam at each output of the turbine is controlled while monitoring the state quantity of the heating steam in the previous stage. In addition to providing the reheat steam temperature, it prevents the operating condition of the subsequent heater alone due to the failure of the preceding heating steam system, etc., and prevents the temperature mismatch between the exhaust pressure of the high pressure turbine and the heating steam that is excessively large. In addition, it is possible to prevent damage due to thermal deformation of the heater due to the temperature difference between the inlet and outlet of the latter stage heater.
[0017]
To achieve the above object, turbines control apparatus of the present invention includes a first stage heater for heating the outlet steam of the high pressure turbine with the extracted steam of the high pressure turbine, a portion of the main steam supplied to the high pressure turbine In the control device for controlling the opening degree of the heating steam control valve for adjusting the flow rate of a part of the main steam of the heater having the second stage heater for heating the outlet steam of the first stage heater using The opening degree of the heating steam control valve is controlled based on the state quantity of the extracted steam of the high-pressure turbine and the state quantity of the outlet steam of the high-pressure turbine.
[0018]
That is, a turbine control device according to the present invention includes a first required state quantity setting device that outputs a first required state quantity set value signal by multiplying a signal of a state quantity of an outlet steam of a high pressure turbine by a first function, and a high pressure turbine. A second required state quantity setter that outputs a second required state quantity set value signal by multiplying a signal of the state quantity of the extracted steam by a second function, and output signals of the first and second required state quantity setters And a low-value priority selector that outputs a signal having a small value, and the opening degree of the heating steam control valve is controlled based on the output signal of the low-value priority selector.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing a configuration of a steam turbine plant that employs a turbine control method according to the present invention. This steam turbine plant includes a steam generator 1, a steam control valve 3 that adjusts the flow rate of main steam 2 supplied from the steam generator 1 to the turbine, and a high pressure that converts thermal energy of the main steam 2 into rotational energy of the turbine rotor. Turbine 4, moisture separator / heater 6 that reheats high-pressure turbine outlet steam 5 that is the exhaust of high-pressure turbine 4, moisture separator 7 that is a component of moisture separator / heater 6, first stage heating Generator 9 and second stage heater 11, low pressure turbine 13 for converting the heat energy of the steam reheated by moisture separator heater 6 into rotational energy, and generator driven by high pressure turbine 4 and low pressure turbine 13 14, a condenser 15 that condenses the exhaust steam of the low-pressure turbine 13, and a feed water heater 16 that raises the temperature of the condensate and supplies the steam to the steam generator 1.
[0021]
Here, the speed of the turbine, the inlet steam pressure, the output, and the like are controlled by adjusting the flow rate of the main steam 2 supplied from the steam generator 1 to the turbine by the steam control valve 3.
[0022]
Further, the steam turbine plant includes a pressure detector 18 that detects the pressure (P ₀ ) of the outlet steam 5 of the high-pressure turbine 4 as a heating steam system related to the moisture separation heater 6, and the first from the high-pressure turbine 4. A pressure detector 19 that detects the pressure (P ₁ ) of the extracted steam 8 of the high-pressure turbine 4 supplied to the stage heater 9, and a second stage heater that is a part of the main steam generated from the steam generator 1. 11 is a heating steam control valve 17 for adjusting the flow rate of the steam 20 supplied to the pressure sensor 11, a pressure detector 21 for detecting the pressure (P ₂ ) of the steam 20, and output signal values of the pressure detectors 21 and the generator 14. And a control device 22 for controlling the heating steam control valve 17.
[0023]
The main steam 2 generated by the steam generator 1 is flow-controlled by the steam control valve 3 and then flows into the high-pressure turbine 4. The high-pressure turbine outlet steam 5 that has worked in the high-pressure turbine 4 separates the moisture in the moisture separator 7 of the moisture separator heater 6 and is reheated in the first stage heater 9 and the second stage heater 11. Electric power is generated by the generator 14 guided to the low-pressure turbine 13 and rotated by these turbines. The steam that has worked in the low-pressure turbine 13 is led to the condenser 15 to become condensed water, and the condensed water is heated by the feed water heater 16 and returned to the steam generator 1.
[0024]
On the other hand, the extraction steam 8 of the high-pressure turbine 4 is led to the first stage heater 9 as heating steam, where the steam 5 flowing from the outlet of the high-pressure turbine 4 and passing through the moisture separator 7 is heated, and a steam generator Part of the main steam 2 fed from 1 is flow-controlled by the steam control valve 1 as heated steam and guided to the second stage heater 11, where the steam 10 flowing from the first stage heater 9 is passed through. Heat. The extraction steam extraction point of the high-pressure turbine 4 is determined by the heat balance of the entire plant.
[0025]
FIG. 2 is a control block diagram of the control device 22 that controls the steam control valve 17 that adjusts the flow rate of the heating steam supplied to the second stage heater 11. The control device 22 will be described in detail next. The first required pressure setter 31, the second required pressure setter 32, the low value priority selector 33, the calculator 34, the proportional integral calculator 35, and the like. , Is composed of.
[0026]
The first required pressure setting device 31 receives the signal P ₀ of the pressure detector 18 that detects the pressure of the outlet steam 5 of the high-pressure turbine 4, and generates the first required pressure setting value signal P ₂ a based on the value of the signal P _0. calculate. The second required pressure setting device 32 receives the signal P ₁ of the pressure detector 19 of the extraction steam 8 of the high-pressure turbine 4 that is the heating steam of the first stage heater 9 and inputs the second based on the value of the signal P ₁ . The required pressure set value signal P2b is calculated. The low value priority selector 33 compares the first required pressure set value signal P2a and the second required pressure set value signal P2b, and outputs the lower value as the set value. Calculator 34, a heating steam set pressure P2c output from the low value preference selector 33, a deviation signal between a signal P ₂ of the pressure detector 21, regulated heating steam 20 in heat steam regulating valve 17 △ P ₂ Is calculated. Then, the proportional-plus-integral calculator 35 outputs a valve opening command signal SL to the heating steam control valve 17 based on the deviation signal ΔP ₂ to adjust the valve opening, and detects the detected pressure P of the pressure detector 21. ₂ is controlled to be the set pressure P2c set by the low value priority selector 33.
[0027]
When the turbine is started and the load increases, the opening of the steam control valve 3 increases, and the amount of steam supplied to the high-pressure turbine 4 increases. Along with this, the pressure P ₀ of the outlet steam 5 of the high-pressure turbine 4 increases, and the first required pressure set value signal P _{2 a} is output from the first required pressure setter 31 by this pressure signal P ₀ . So that optimum heating steam flow to the heat exchange amount in the second stage heater 11 relative to the pressure P ₀ of the outlet steam 5 of the first request pressure setter 31 in the high-pressure turbine 4 is obtained, the first required pressure by a function A set value signal P2a is defined. On the other hand, the pressure P ₁ of the extraction steam 8 of the high-pressure turbine 4 also increases with load increase of the turbine, the pressure signal P ₁ from the second required pressure setter 32 second required pressure setpoint signal P2b is output. So that optimum heating steam flow to the heat exchange amount in the second stage heater 11 relative to the pressure P ₁ of the second required pressure setter 32 in the extraction steam 8 of the high-pressure turbine 4 is obtained, the second required pressure by a function A set value signal P2b is defined. The first required pressure set value signal P2a and the second required pressure set value signal P2b are input to the low value priority selector 33, and the lower pressure is selected and output as the heating steam set pressure P2c. The deviation signal △ P ₂ of the pressure signal P ₂ detected by the pressure detector 21 of the heating steam set pressure P2c the heating steam 20 is output is calculated by the calculation 34. A valve opening command signal SL is output from the proportional-plus-integral calculator 35 to the heating steam control valve 17 so as to control the detected pressure to the set pressure based on the deviation signal ΔP ₂ to obtain a prescribed heating steam flow rate It is.
[0028]
Here, a function setting method of the first required pressure setting device 31 and the second required pressure setting device 32 for providing the optimum amount of heating steam will be described.
[0029]
FIG. 3A shows the vapor temperature characteristics when passing through the first stage heater 9 and the second stage heater 11. In the first stage heater 9, the high-pressure turbine outlet steam temperature T ₀ (for example, 192 ° C.) and the first stage heater steam temperature T ₁ (236 ° C.) are heat-exchanged, and the first stage heater outlet temperature T ₁ ′ (222) ° C) is obtained. In the second stage heater 11, the first stage heater outlet temperature T ₁ ′ (222 ° C.) and the second stage heating steam temperature T ₂ (282 ° C.) are heat-exchanged, and the second stage heater outlet temperature T ₂ ′. (264 ° C.) is obtained. The inlet / outlet temperature difference ΔT ₁ (30 ° C.) of the first stage heater 9 is uniquely determined because the high-pressure turbine 4 outlet steam flow rate and the high-pressure turbine 4 extraction steam flow rate are generally proportional. Since the inlet / outlet temperature difference ΔT ₂ (42 ° C.) of the second stage heater 11 is determined by the heating steam flow rate, it can be controlled by the control device 22. Inlet and outlet temperature difference between the inlet and outlet temperature difference △ T ₁ and a second stage heater 11 of the first stage heater 9 from these △ T ₂ within the specified values, can be set to for example, within 55 ° C., respectively.
[0030]
FIG. 4A shows an example of temperature characteristics when the heating steam pressure is controlled by setting the heating steam pressure by the control method of the present invention. Each steam temperature rises as the turbine output increases, but the relationship among the high-pressure turbine 4 outlet steam temperature T ₀ , the first stage heater 9 outlet temperature T ₁ ′, and the second stage heater 11 outlet temperature T ₂ ′. first stage inlet and outlet temperature difference △ T ₁ and a second stage heater 11 inlet and outlet temperature difference △ T ₂ is a temperature such that the specified value does not become a problem in the thermal deformation of the heater during the entire load range of the heater 9 by Characteristics are obtained.
[0031]
FIG. 3B shows temperature characteristics when the supply amount of the first stage heating steam 9 is decreased due to an erroneous operation or failure of an operator without using the control method of the present invention. Since the steam pressure P ₁ and the temperature T ₁ decrease with the decrease in the first stage heating steam amount and the heating amount by the first stage heater 9 decreases, for example, the outlet temperature T ₁ ′ of the first stage heater 9 is 200. When the temperature reaches 0 ° C., the temperature difference from the second stage heating steam temperature T ₂ (282 ° C.) increases, and the inlet / outlet temperature difference ΔT _{2 of} the second stage heater 11 also increases, resulting in excessive thermal stress on the heater. Occurs and heat deformation occurs. FIG. 4B is a diagram showing a defective state as shown in FIG. 3B corresponding to the turbine output.
[0032]
FIG.3 (c) shows the temperature characteristic when the control method of this invention is implemented and the supply amount of 1st stage heating steam reduces similarly to FIG.3 (b). With decreasing the supply amount of the first stage heating steam, the first heating steam pressure signal P ₁ is reduced, also reduced the second required pressure setpoint signal P2b from the second required pressure setter 32, and finally heated The steam flow is reduced by the steam control valve 17. As the heating steam flow rate decreases, the second stage heating steam temperature T ₂ also decreases and is supplied to the second stage heater 11, so the first stage heater outlet temperature T ₁ ′ and the second stage heating steam temperature T _2. temperature difference between the (T ₂ -T ₁ ') is kept small, also inlet and outlet temperature difference of the second stage heater 11 △ T ₂ becomes small, it is possible to prevent the occurrence of thermal deformation of the heater. FIG. 4C shows temperature characteristics in which the state controlled as shown in FIG. 3B corresponds to the turbine output.
[0033]
FIG. 5 is a diagram showing a process of creating a function used in the first required pressure setting device 31 (FIG. 2). FIG. 5A shows the high-pressure turbine outlet steam pressure P ₀ , high-pressure turbine outlet steam temperature T ₀ , first stage heater outlet temperature T ₁ ′, and second stage heater outlet temperature T ₂ ′ corresponding to the turbine output. Show the relationship. This is obtained sufficiently doorway temperature difference △ T suppressed ₁ and the value of the inlet and outlet temperature difference △ T ₂ of the second stage heater 11 within a prescribed value, and the heat exchange amount of the heating device of the first stage heater 9 It is set as follows. FIG. 5 (b) also shows a turbine output and the second stage heating steam pressure P ₂ and the second stage heater relationship outlet temperature T _2. Here, by adjusting the second stage heater outlet temperature T ₂ ′ in FIG. 5B to the target value T ₂ ′ in FIG. 5A, as shown in FIG. A relationship between P ₀ and the second stage heating steam pressure P ₂ (P ₂ = f (P ₀ )) can be created. Note _{P 2} in FIG. 5 (c) corresponds to P2a in FIG.
[0034]
FIG. 6 is a diagram showing a process of creating a function used in the second required pressure setting device 32 (FIG. 2). FIG. 6A shows the turbine output, the first stage heating steam pressure P ₁ , the high pressure turbine outlet steam temperature T ₀ , the first stage heater outlet temperature T ₁ ′, and the second stage heater outlet temperature T ₂ ′. Show the relationship. FIG. 6B also shows the relationship between the turbine output, the second stage heating steam pressure P _2, and the second stage heater outlet temperature T ₂ ′. From these two relations, the second stage heater outlet temperature T ₂ ′ is adjusted to the target value T ₂ ′ in FIG. 6A, and the first stage heating steam pressure P _{1 as} shown in FIG. 6C. And the second-stage heating steam pressure P ₂ (P ₂ = f (P ₁ )). Wherein _{P 2} in FIG. 6 (c) corresponds to P2b in FIG.
[0035]
In addition, when there is no supply of 2nd stage heating steam, only the heat exchange by the 2nd stage heater 11 is lost, and there is no problem in damage to a heater.
[0036]
In the present embodiment, a method of controlling the flow rate of each steam by measuring the steam pressure has been described. However, instead of the pressure, the flow rate is directly measured with a flow meter, or the high-pressure turbine outlet steam pressure is A similar effect can be obtained even when turbine power having a substantially proportional relationship is used.
[0037]
【The invention's effect】
According to the present invention, in a steam turbine having a reheat system of two or more stages, the heat exchange amount in each stage heater can be stably obtained through the entire output operation state of the turbine, and the supply of heated steam for some reason. Even when an abnormality occurs, the amount of heating steam is automatically controlled, so that protection against thermal deformation and thermal stress of the heater can always be realized.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a steam turbine plant using a turbine control method of the present invention.
FIG. 2 is a control block diagram of the turbine control device.
FIG. 3 is a diagram showing steam temperature characteristics in a heater using the control method of the present invention, compared with a case where the control method is not used.
4 is a steam temperature characteristic obtained by developing the steam temperature characteristic shown in FIG. 3 corresponding to the turbine output.
FIG. 5 is a diagram illustrating a function used in a first required pressure setter of the turbine control device.
FIG. 6 is a diagram illustrating a function used in a second required pressure setting device of the turbine control device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Steam generator 2 Main steam 3 Steam control valve 4 High pressure turbine 5 High pressure turbine exit steam 6 Moisture separation heater 7 Moisture separator 8 High pressure turbine extraction steam 9 First stage heater 11 Second stage heater 13 Low pressure turbine 14 Generator 15 Condenser 16 Feed water heater 17 Heated steam control valve 18, 19, 21 Steam pressure detector 22 Turbine controller 31 First required pressure setter 32 Second required pressure setter 33 Low value priority selector 34 Calculator 35 Proportional integral calculator P ₀ High pressure turbine outlet steam pressure P ₁ First stage heating steam pressure P ₂ Second stage heating steam pressure T ₀ High pressure turbine outlet steam temperature T ₁ First stage heating steam temperature T ₁ ′ First Stage heater outlet temperature T ₂ Second stage heater steam temperature T ₂ ′ Second stage heater outlet temperature

Claims (3)

The high pressure turbine outlet that has flowed in to reheat the outlet steam of the high pressure turbine driven by the main steam supplied from the steam source through the steam control valve and to supply the reheated steam for driving the low pressure turbine. A first stage heater that heats steam by exchanging heat with the extracted steam of the high pressure turbine extracted from the high pressure turbine, and a steam heated by the first stage heater, and a heating steam control valve from the steam source In a turbine control method comprising a heater composed of a second stage heater that is heated by exchanging heat with a part of the main steam introduced through the second steam heater,
Heat exchange in the first stage heater based on the temperature and flow rate of the steam calculated from the pressure of the outlet steam of the high-pressure turbine and the temperature and flow rate of the extracted steam calculated from the pressure of the extracted steam of the high-pressure turbine Calculating the temperature of the outlet steam of the first stage heater that is reheated and flowing out, and the temperature and flow rate of the outlet steam of the first stage heater and the temperature calculated from the pressure of a part of the main steam, The flow rate of a part of the main steam introduced into the second stage heater is calculated as follows, that is, the part flow rate of the main steam is reheated by heat exchange in the second stage heater. The temperature difference between the outlet steam of the second stage heater flowing out and the outlet steam of the first stage heater is equal to or less than the temperature difference defined by the allowable deformation amount of the second stage heater. Calculate as the flow rate and control with the heating steam control valve so that the flow rate is reached Turbine control method comprising and. The high pressure turbine outlet that has flowed in to reheat the outlet steam of the high pressure turbine driven by the main steam supplied from the steam source through the steam control valve and to supply the reheated steam for driving the low pressure turbine. A first stage heater that heats steam by exchanging heat with the extracted steam of the high pressure turbine extracted from the high pressure turbine, and a steam heated by the first stage heater, and a heating steam control valve from the steam source In a turbine control method comprising a heater composed of a second stage heater that is heated by exchanging heat with a part of the main steam introduced through the second steam heater,
Optimum for heat exchange in the second stage heater with respect to the steam pressure at the outlet of the high-pressure turbine, because the amount of second stage heating steam supplied to the second stage heater specified according to each turbine output is supplied A second stage heating steam pressure set value is set based on the high-pressure turbine outlet pressure using a function for obtaining a pressure corresponding to the amount of heating steam, and the second-stage heater is further set against the high-pressure turbine extraction steam pressure. Using the function for obtaining the pressure corresponding to the amount of heating steam optimal for heat exchange in the factory, the second stage heating steam pressure set value was set based on the first stage heating steam pressure, and was set from the high pressure turbine outlet steam pressure. The second stage heating steam pressure setting value is compared with the second stage heating steam pressure setting value set from the first stage heating steam pressure, and the lower one of the two setting values is given priority to the second stage heating. Set the steam pressure as the final set value, and add a second value to the final set value. Turbine control method characterized by controlling the opening of the heating steam regulating valve by a feedback control so that the steam pressure becomes. A first stage heater that heats the outlet steam of the high pressure turbine using the extraction steam of the high pressure turbine, and a part of the main steam that is supplied to the high pressure turbine is used to heat the outlet steam of the first stage heater. In the turbine control device that controls the opening degree of the heating steam control valve that adjusts the flow rate of a part of the main steam of the heater having the second stage heater,
Based on the state quantity of the extraction steam of the high-pressure turbine and the state quantity of the outlet steam of the high-pressure turbine, the opening degree of the heating steam control valve is controlled , and the state quantity of the outlet steam of the high-pressure turbine is A first required state quantity setter that multiplies the signal by a first function and outputs a first required state quantity set value signal; and a second function that multiplies the signal of the state quantity of the extracted steam of the high-pressure turbine by a second function. A second required state quantity setter that outputs a requested state quantity set value signal, and a signal having a smaller value of either the output signal of the first required state quantity setter or the output signal of the second required state quantity setter is output. And a low-value priority selector for controlling the opening degree of the heating steam control valve based on an output signal of the low-value priority selector .

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